System of Equations...?

Question

I am confused on this problem and was wondering if anyone could help me. I would appreciate it greatly!

Pandit is an aging dog who has to be kept on a strict containing, among other things , 4.6 grams of protein and 4.2 grams of fat. Two dog foods are available to Pandit's owner.

i.) Food A has 10% protein & 6% fat, while
ii.) Food B has 4% protein & 6% fat.

How many grams of food A should Pandit's owner use in his diet?

Thanks again for any help!

Answer 1

x gram of A and y gram of B would give
0.06x + 0.06y grams of fat
and
0.1x + 0.04y grams of protein.

Applying this to the diet requirements gives
6x + 6y = 420
10x + 4y = 460

How much help do you need to solve these? Finish it yourself?
x + y = 70
5x + 2y = 230
3x = 90
x = 30, y = 40
so it's 30g of A.

Answer 2

Let x= grams/day of food A
Let y=grams/day of food B

The protein balance. 0.1A + 0.06B=4.6
The fat balance. 0.06A + 0.06B = 4.2
Solve these for A.