Question

A farmer has 268 cows and each cow has either 1 or 2 calves. If there are 335 calves, what fraction of the cows have 2 calves?

Answer 1

I'll use S for a cow that has a single calf, and T for a cow that has two calves. There's 268 cows total, so :

S+T = 268

There's 335 calves total, so 1*S + 2*T will be equal to 335.

S+2T = 335

Answer 2

So now you have a system of two equations and two variables to solve:

S+T = 268
S+2T = 335

Try solving this for T, since we want the fraction with 2 calves. And remember the fraction means the number of cows with two calves over the total number of cows, or T/(S+T)

Answer 3

ie T/268 will be your fraction

Answer 4

Thanks so much for clearing this up for me.
And I got my answer...

If each cow has one calf, then there are a total of 268 calves.
So we take the given number and minus it from the total number of calves.

335-268=67.

67 cows have 2 calves.

Our fraction is 67/268, which, when simplifies, is; 1/4.

Answer 5

Yep :) Your method is actually a bit easier than the way I showed you.