Four tins of cat food are sufficient to feed 3 cats for 7 days. How many tins of cat food is needed to feed 2

3 cats for 7-days require = 4 tins
1 cat for 7-days require = 4 / 3 tins
2 cats for 7-days require = 4 x 2 / 3 = 8/3 tins >=====< ANSWER

4 tins are good for 3*7 = 21 cat days so each tin is good for 21/4 cat days or each cat day requires 4/21 tins. Two cats for 7 days is 14 cat days which requires 14*4/21 = 8/3 tins. But, since you can't buy partial tins of cat food, you will need 3 tins.

2 1/3 tins of food. Since 2 cats is 2/3 of 3 cats, you need to know what 2/3 of 4 is. 2/3(4)= 8/3 or 2 2/3.

Solution,
3 cats can feed 4 tins of cat food.
1 cat can feed 4/3 tins of cat food.
2 cats can feed 4×2/3 tins of cat food.
= 8/3 tins of cat food.

Each cat will eat 4/3 tins of cat food

So two cats will eat 2(4/3) = 8/3 = 2.7 tins

Was it really sufficient? You had 3 cats and now you have two. Maybe that other cat needed more food.

For 7 days, 2/3 of 4 or 8/3 cans