The restaurant

Algebra Level 2

Some friends went to a restaurant and decided to eat the same dish. After eating, each one was expected to pay his own bill. But three friends had no money to pay the bill, so each of the others paid Rs 3 more than their own bill. If the total bill was Rs 180, how many friends were there?

The answer is 15.

2 solutions

Sachin Mittal
Aug 15, 2014

since all the frnds with money will pay 3 INR extra for the 3 frnds i.e. they r paying 1 INR extra for 1 frnd.......now let the no. of frnds with money be x,then amt of money on each dish will be x..&..total no. of frnds will be x+3..hence eq. can be written as..............(x+3)*(x)=180 ...........& ......solving it we get x=12...hence total no. of frnds are=>15

13 is also correct for eg da price of 1 dish was $15 n 3people didnt pay meaning 10 paid $15 + $3 xtra which equals 10*18= 180

Pritesh Prasad - 6 years, 9 months ago

u must check out your answer once again

sachin mittal - 6 years, 9 months ago

13*15 is not equal to 180

Shubham Bhardwaj - 6 years, 5 months ago

Roger Erisman
May 14, 2015

Let x = number of friends and x - 3 = number who paid for meal.

The average cost per meal should have been 180/x.

The actual average cost was 180/(x-3), which equal 180/x + 3. (Since each paid 3 extra)

Getting rid of denominators ===>180 x = 180 x - 540 + 3 x^2 -9 x

Solve: 0 = 3 x^2 - 9 x -540 ====> divide by 3 ==> 0 = x^2 -3*x -180

Factors as (x+12)*(x-15) = 0 so x = 15 or -12, Discard negative x = 15

The restaurant

The answer is 15.

2 solutions

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