7 cows (all together) eat 7 fields in 7 days

→ 1 cow eats 7 fields in $7\times7=49$ days.

→ 1 Cow eats 1 field in $49\div7=7$ days.

→ 1 cow eats 5 fields in $7\times5=35$ days.

→ 5 cows eat 5 fields in $35\div5=7$ days.

Answer is 7

Because of 7 cows need 7 days to eat 7 fields, then we can conclude that a cow need 7 days to eat one field.

Thus it doesn't matter whether the number of cow and field are same.

The number of fields are in direct proportion to the number of cows and to the number of days.The number of cows are in direct proportion to the number of fields and inversely proportional to the number of days.

F=KCD where F= # of fields, K is the constant, C= # of cows, and D= #of days

In this situation K= 1/7,
7= 1/7x7x7

In the new situation, 5= 1/7x5xD Solving for D we get 7.

Try this problem: How long would it take 4 cows to eat 8 fields?

Let the unknown no. be Y,

(7x7)/(5xY)=7/5

49/5Y=7/5

49/35=Y/5

Y=1.4x5

Y=7

--> 7 cows eats 7 fields in 7 days.

--> 1 cows eats 1 fields in 7 days.

--> 2 cows eats 2 fields in 7 days.

--> 5 cows eats 5 fields in 7 days

If you're getting hung up on this forget the fact that all the base numbers are seven.

If 7 cows take 7 days to eat 7 fields, it takes those same seven cows one day to eat one field.

Knowing this, each cow eats 1/7th of a field a day. So, one cow eats 5 fields in 35 days (7 cow days to a field times 5 fields). Many cows make light work, and 5 cows can do 35 cow days worth of work in 7 days.

QED.

7 cows take 7 days to eat 7 fields of grass. Assuming each cow is uniform in their eating habits then 1 cow will eat (1/7) fields a day. Therefore 5 cows will eat (5/7) fields a day. So we have (5/7)X = 5 because the amount of time is the variable within this situation. Then solve for X by either dividing each side by (5/7) or just intuitively see the answer which is 7.

You can start by imagining the following to make it much more intuitive and fun: • Replace the grass fields with super pizzas. • Replace the Cows with people. • Keep the numbers the same.

Now the problem reads: If 7 people need 7 days to eat 7 super pizzas, how long would it take 5 people to eat 5 super pizzas? Now for deduction:

=> There are 7 people eating a super pizza on day one. That means each had one piece. Therefore there are 7 pieces for each pizza.

=> 5 people are to eat 35 pieces [5 pizzas x 7 pieces = 35]

=> They can only eat 1 slice a day so they remain with 2 extra slices for each day they attempt to eat a pizza. 5 days 5 pizzas.

=> Now since there are two slices extra per day 5(2) = 10 pieces are left. So the people spend 2 extra days eating leftovers.

=> In the end they took 5 days plus 2 extra days to finish the task. So the answer is... Wait for it... 7

Let $c$ be the number of cows, $f$ be the number of grass fields ate by the cows, and $d$ be the number of days.

The statement

7 cows need 7 days to eat 7 grass fields

can be algebraically formulated as: $7c=\frac{7f}{7d}$ Dividing both sides by 7 we get: $c=\frac{f}{7d}$ Multiplying both sides by 5 we get: $5c=\frac{5f}{7d}$

Translating back the last algebraic equation into a statement we get:

5 cows need 7 days to eat 5 grass fields

One cow eats one field of grass in 7 days. Therefore 5 cows can eat 5 fields in the same 7 days.

We can write the next equation with the information of the problem:

7/7/7=5/5/x

Then:

1/7 = 1/x Finally we obtain the value of x:

x=7 days

This was similar to how I solved it but I just worked with the raw values. 7=1.4×5 as it takes 7 cows to eat 1 field a day it takes 5 cows 1.4 days to eat 1 field therefor days=fields × 1.4 to summarize 5×1.4=answer(7)

We can solve it like this: If 7 cows need 7 days to eat 7 grass fields, this means that 35 cows need 7 days to eat 35 grass fields. Now, we can see that If the number of cows is equal to the number of grass fields, the number of days it will take is always 7.

so 49 cowdays is needed to 7 grass fields to be eaten

So to eat 1 grass field it needs 7cowdays

So to 5 grass fields it needs 5*7= 35 cowdays

So 35 cowdays divided by 5 cows is 7 days.

Bon apetite!

7 cows eat 7 fields in 7 days.
Which means 1 cow eats one field in 7 days.
Which also means 5 cows eat 5 fields in 7 days.

1 grassfield takes 7 cows to eat in 1 day, which gives 1 cow eats $1/7$ grassfields/day, so 5 cows would eat 5/7 grassfields/day, so 5 grassfields would take $5grassfields/(5/7grassfields/day)=7 days$

It takes 7 cows, eating for 7 days to munch on 7 fields.

This can be restated as follows:

It takes 49 Cows * Days to eat 7 fields

So it takes 7 Cows * Days to eat 1 field

Since we need to have 5 times the number of fields to be eaten we would need five times the number of Cows* Day , therefore 35 Cows * Days will get the job done.

We know that 5 cows are willing to work, thus we need them for 7 Days (5 Cows * 7 days = 35 Cows * Days )

7 cows→7 days→7 field, so,1 cow→7 days→1 field then, 5 cows→7 days→5 fields

If they ate 7 grass fields then there is no need to eat 5 because they were already eaten. Logic or math

7 cows 7 days 7fields:

5 cows would therefore take 7/5 (1.4) of the time to eat the same amount.

However only 5 fields need to be eaten so:

Number of fields × time factor = 5 × 1.4 = 7

If 7 cows * 7 days = 7 fields, then it takes 49 cowdays to eat 7 fields. (Sounds weird, right?)

Therefore:

• 49 cowdays = 7 fields --> Divide by 7/5 on both sides (or multiply by 5/7)

• 35 cowdays = 5 fields --> We know that cows * days = cowdays, so...

• 35 cowdays = x cows * 5 days --> We are given 5 days, but don't know the number of cows.

• 7 cows = x cows --> Divide by 5 days on both sides to get the number of cows, x.

Need 7 cows to make this possible.

If 7 cows take 7 days to eat 7 fields, then it takes each cow 7 days to eat 1 field. The number of cows doesn't change the rate at which 1 cow can eat 1 field. So as long as the cow to field ratio is 1:1, the answer will be 7 days.

1 cow in 1 day eats 1/7th of a field..

So 5 cows in 1 day eat 5/7th of a field..

Let x be the no. of days. Therefore, for 5 cows to eat 5 fields.. x*5/7 = 5

i.e.

(no. of days) * (no. of cows * per day per cow eat) = no. Of fields

So x=7

the answer can be 5 as 5 cow need 5 days to eat 5 grass fields.as 7 cows need 7 days to eat 7 grass fields

You dont need to think too much on this.

If 7 cows eat 7 fields in 7 days.. Means each cow eats 1 field in 7 days? Take away 2 cows (thus to be 5 cows) It wont shorten or lenghen the days..

So 5 cows eat 5 fields in 7 days no?

we can solve it by [short & long time calculation]

• 7 cow eats 7 fields = 7 day need

• 1 cow eats 7 fields = 7*7 day [1cow need long time to finish ,so multiply]

• 1 cow eats 1 field = (7*7)/7 day [1 cow 1 fiend need short time,so divide] = 7 day

• 1 cow eats 5 fields= 7*5 day [long time, mmultiply]

• 5 cow eats 5 field =(7*5)/5 day [short time, divide]

                          = 7 day
  

Let the speed of eating grass fields be V.

$V = \frac{7}{7} \frac{field}{day} = 1 \frac{field}{day}$ for 7 cows

Therefore if we assume that all cows contribute equally to the speed, we have:

$7V = 1$ for 7 cows $5V = x$ for 5 cows

Solving this for x gives the speed of $\frac{5}{7} \frac{field}{day}$

Which means they'll need 7 days as well.

5 cows need 1.4 days to eat one field and 7 days to eat 5. (7/5×5).

• 1 cow eats 1/7 field in a day
• 5 cows will eat 5/7 field in a day
• 5 field will be eaten by 5 cows in 7 days

It takes seven days for seven cows to eat seven fields. So lets assume that each cow has her own field. It will take each cow seven days to eat a field so that together, seven will have been eaten.