What is the opposite of +50?

Algebra Level 2

Muthu the shopkeeper was having a hard time making enough profit in his store, so he decided to increase his prices, and declared to his employees “Raise all prices by 50%!”.

But instead of increasing his revenue, this just caused all of his customers to abandon him, and now he's making no profit at all. He wants to reverse his decision, and declares to his employees “I've changed my mind. Cut all prices by 50%!”.

What is the net effect of these two decisions?

No net change to sale prices. Sale prices went down by 50%. Sale prices went up by 25%. Sale prices went down by 25%

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35 solutions

Prasun Biswas
Feb 26, 2014

We see that initial selling price = $ 200 =\$200 . Now, the shopkeeper says to increase the selling price by 50 % 50\text{\% } . Then----

Selling price (after raise in price) = $ 200 + 50 100 × $ 200 = $ 200 + $ 200 2 = $ 200 + $ 100 = $ 300 =\$200 + \frac{50}{100}\times \$200 = \$200+\$ \frac{200}{2}=\$200+\$100= \$\boxed{300}

Now, when the shopkeeper is pissed off on not having any profit, he decides to cut down prices by 50 % 50\text{\%} , i.e., reduce price by 50 % 50\text{\%} of $ 300 \$300 not $ 200 \$200 as $ 300 \$300 is now the selling price. Then---

Selling price (after fall in price) = $ 300 50 100 × $ 300 = $ 300 $ 300 2 = $ 300 $ 150 = $ 150 =\$300 - \frac{50}{100}\times \$300 = \$300 - \$\frac{300}{2}=\$300-\$150= \$ \boxed{150}

Now, since final selling price is less than original selling price at the beginning, so obviously the prices went down. He is selling the products at $ ( 200 150 ) = $ 50 \$(200-150)=\$50 less than his original $ 200 \$200 price.

So, net change by the decisions = 50 200 × 100 = 1 4 × 100 = 25 % =\frac{50}{200}\times 100 =\frac{1}{4}\times 100 = \boxed{25\text{\%}}

So, The prices went down by 25% .

initially 200$ increased by 50% results 300$.Then reduced 50% of 300$ results 150$. i.e. loss of 50$ in the initial price which is nothing but 25% of 200

Anishchandran C - 7 years, 3 months ago

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Thanks so much for making it understandable!

Vaishala Thirugnanasampanthar - 7 years, 1 month ago

Thanks! ;)

Kou$htav Chakrabarty - 7 years, 3 months ago

thanks that's very nice:)

Venkata Nikhil - 7 years, 3 months ago

ty

Atsiv Kram - 7 years, 3 months ago

I could not do it.

Muhammad Hassan - 7 years, 3 months ago

Wow Nice Great

Matthew Magsano - 7 years, 3 months ago

Here when the shopkeeper increases all the prices by 50% and then the shopkeeper again decreases the prices by 50%. Therefore 50% - 50% = 0% i.e. no changes in the price.

Rahul Chudasama - 7 years, 2 months ago

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No, it is not so. When the prices were increased by 50 % 50\% , the increment in price was 50 % 50\% of $ 200 \$200 but when the price went down, the price went down by 50 % 50\% of $ ( 200 + 100 ) = $ 300 \$(200+100)=\$300 not $ 200 \$200 , so both the increment and decrement are not same. Actually, the decrement is higher than the initial increment, so the net effect of the decisions was the price going down by 25 % 25\% of the original price. Hope this helps..... :)

Prasun Biswas - 7 years, 2 months ago
Aritri Chatterjee
Feb 23, 2014

100 TO 150 TO 75 IS 100 TO 75 IS 25 % REDUCTION

+50-50-2500/100=-25%

manoj negi - 7 years, 3 months ago

me 2

Gaurav La - 7 years, 3 months ago

I did the same way!

Ameya Salankar - 7 years, 3 months ago

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coz it is the right(est) way;)

Aakarshit Uppal - 7 years, 3 months ago

applied the same method...

vishal MaYHeM - 7 years, 3 months ago

i get it

deepthi prakash - 7 years, 3 months ago

apply successive percentage rule...

manoj negi - 7 years, 3 months ago

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how is successive percentage rule done?

ruchika patro - 7 years, 2 months ago
Harmeet Saluja
Feb 24, 2014

let the initial price be x. rise in price was 50%of x=3/2x. after reduction of 50% the price was 3/2x-50%of 3/2x.=3/4x. now the price was 75% of initial one so there was a reduction of 25%

Joshua Ong
Feb 24, 2014

Let the average price of a dog be x. At first, the shopkeeper raises the prices to 1.5x(which is x times 150%). Then, he cuts the prices, reducing the prices to 0.75x(which is 1.5x divided by 2). Thus, the net decrease in price is 25%

PradyGame Dev
Feb 24, 2014

The general formula for these kind of questions is r^2/100 where r is the rate of percentage change. This only applies when increase% = decrease%. For example, If Cost Price of something is Rs.100 and you sell two of these items at a gain of 20% and loss of 20%, then percentage change is (20 * 20) / 100 = 4, which is a loss of 4%.

In this problem, we do (50 * 50)/100 =25(%)

Kamal K
Feb 26, 2014

K is the object.... K will going to increase by 50% resultant is S.P= 150% of C.P=>150K/100 Finally, Owner had changed his mind and decrease the object by 50% so, 50/100(150K/100)=3K/4.so, remaining is 1/4=0.25 our answer is in %..so 0.25*100=25%

Rajat Gupta
Feb 24, 2014

let the price be x. when we increase it by 50% it will become 1.5x. Now if we decrease it by 50% it will now become 0.75x which is 25% less then actual price i.e. x. So the cost will went down by 25%.

Nathan Blanco
Feb 24, 2014

Think of a dollar made up of 4 quarters. Increase by 50% brings you to $1.50, then half of that is 75 cents. This is a 25% decrease from the original dollar.

Arijeet Satapathy
Feb 24, 2014

the formula is x^2/100 where x = the % going up and down. Moreover there is always a loss in this case.

Therefore, here x=50, x^2/100 = 2500/100 = 25

Therefore , the price will go down by 25%

I worked mine out the same way

Kaylene Pillay - 7 years, 3 months ago

Let name sale prices "a", prices after increasing of 50% "b" and prices after deacreasing of 50% "c"... b=a + 50% a, it means b= 1,5 a .. c= b- 50% b it means c= 0,5 b then c= 0,5 ( 1,5 a) so c=0,75 a... in conclusion the sale prices went down by 25%..

I'm with Aritri...using 100 is easiest!

Micah Mzumara
Mar 18, 2014

The new price after increase become $300. After the second reduction by 50% it become $150. The new price becomes less by $50 to the original price. Find the percentage of $50 out of $200. This gives 25%:hence reduced by 25% from the original price.

Khandakar Rahman
Mar 16, 2014

Increasing 50%, it goes to 150. After reducing the 50%, it goes to 75%. So, net decrease is 100% - 75% = 25%

Rohit Kshatriya
Mar 14, 2014

let say product price is 100 and he has raised 50 percentage. so it will come 150. now he has decided to fall down the price to 50%... so it will 150*50% =75 .... thus it went down to 25 percentange

Swagata Paul
Mar 11, 2014

Initial price=200$. After 50% increase of the prices, new price=300$. Noe the price is cut down by 50% from the latest price. So the new price becomes=300-150=150$. So the original price went down by 25%.

Let the initial selling price = Rs 100
Shopkeeper increased the selling price by 50%
Therefore, now the selling price = Rs 150
Again, he reduces it to 50%
That is now, selling price = Rs 75 So the difference is Rs 25
That means, the decrease is 25%




let the initial price be constant "K". ;
K + 0.5K = 1.5K

now, let 1.5K = L ;
L - 0.5L = 0.5L ;
substitute K to L, ;
0.5(1.5K) = .75K ;
in other words, the initial price decreases by 25%.



200+50% of 200 = 300 300-50% of 300 = 150 200-150 = 50 50/200 x 100% = 25%

Harshal Khachane
Mar 8, 2014

for simplicity lets take initial selling price=100 after 50% increase selling price=100+(100x50/100)=150; again reducing selling price to half =150-(150x50/100)=75;

so present selling price =75=100(intial seeling price)-25; so prices went down by 25% .

Muhamed Medo
Mar 6, 2014

we can consider that the price 1000 LE. since he first increased prices by 50% ..... (50% of 1000 =500 LE).... so the price became 1500 LE and when he had to decrase price by 50%...... (50% of 1500 = 750 LE) so the lost is 25%

Navin Kumaran
Mar 6, 2014

This could be an easy calculation

  1. let the original price be 100%

  2. then he add 50% to all price which sum up into 150% (current price)

  3. then he reduce the current price by 50% , means half of the current price, sum up into 150 / 2 = 75%

  4. the original price was 100%, and now its 75%.. so the reduction is 25%..:)

Aviral Chauhan
Mar 6, 2014

Let the prices be 100 then100 + 50% = 100 + 50 = 150, Now 150 - 50% = 150 - 75 = 75. This means prices reduced 25%.

Saurav Sah
Mar 6, 2014

1.5*0.5=7.5.so it is 75% price now which is 25% less than other

Krishna Garg
Mar 6, 2014

Suppose initially price was increased by 50 % that is200 $ was made 300$. Next decision was to reduce theprice from 300$ by 50% that means price was 150 $ now. Therefore,net redution is from 200$ to 150 $ that is 25% Answer

K.K.GARG.India

David Jiang
Mar 5, 2014

First he increase price by 50% which is equivalent to multiplying by 1.5 or 3/2. Then he cuts the price, so multiply by 0.5 or 1/2.

3/2 * 1/2 = 3/4

The result is 3/4 which is 75% of the original price thus a 25% decrease.

let initial price be 100 $ increased price will be 100 + (50% of 100) i.e. 100 + 50 = 150 $ now, decrease it by 50% we get : 150 - (50% 0f 150) i. e. 150 -75 = 75 $ . Now comapring 100 $ with 75 $ we ll observe that sales went down to 25% finally

let initial sp=x sp increased by 50% => new sp = x+ x 50% = 3x/2 now sp desreased by 50% => new sp = 3x/2 - 50% 3x/2 = 3x/4 decrease in sp = (x- 3x/4)/100 = 25%

please avoid using variable , because it increases complexity ..

गौरांग मिश्रा - 7 years, 3 months ago
Muhammad Abdeen
Mar 2, 2014

Consider the price is 100$.. With 50 % increase it will be 150$.. It's now (150)With 50% decrease again. Take half of 150 it will be 75.. Comparing it with the first normal price 100 we will find 25 decrease which is 25% down .. It's very simple

Azza Sekarnova
Mar 1, 2014

Let just the price be X The selling price = X Increase the selling price by 50%, so X + 50/100 · X = X + 0.5X = 1.5X Then decrease the sp by 50%, so the final sp is: 1.5 X - 50/100 · 1.5X = 1.5X - 0.75X = 0.75X It means that he is selling the products at ( 1 - 0.75 ) = lower 0.25 from the beginning price = less ( 0.25 · 100 ) = less 25% from the original price.

Luke Johnson
Mar 1, 2014

When he raises the price by 50% the price is at 150%. Then you can find out easily that 50% of 150% is 75% which is 25% less than 100%

Aravind Raj
Feb 28, 2014

initial selling price =200 Selling price after raise in price =300 selling price after fall in price=150 Net chsnge=50/200*100=25%

Badagha Jivan
Feb 28, 2014

100 TO 150 TO 75 IS 100 TO 75 IS 25 % REDUCTION

Let the initial price be Rs.200. When the shopkeeper increases the selling price by 50% the selling price becomes 200+50% of 200=200+100=300. Now, the shopkeeper decides to decrease the selling price by 50%. Here, we are decreasing the current selling price by 50% and not the original one. Therefore, we get 300-50% of 300=300-150=150. Now 200-150=50 which is 25% of 200. Hence, the selling price has gone down by 25%

let the original sp be 100, after increasing 50 % it became 150, now reduce it by 50 % thus reducing by 75 so the final sp 75, a reduction of 25 %

Rajgopal P
Feb 26, 2014

X + 0.5X = 1.5X. 1.5X /2 = 0.75X

ie., X - 0.75X = 0.25X ie., 25% down

can i explain

John Piecco - 7 years, 3 months ago

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