andrecrompton wrote:

Food Num. of calories per kilogram Num. of grams of protein per kilo

S 2,000 150

T 1,500 90

36. The table above gives the number of calories and grams of protein per kilogram of food S and T. If a total of 7 kilograms of S and T are combined to make a certain food mixture, how many kilograms of food S are in the mixture?

(1) The mixture has a total of 12,000 calories.

(2) The mixture has a total of 810 grams of protein

I REALLY NEED A GOOD EXPLAINATION ON THIS ONE.

the answer should be D.

i. using trail and error, s = 3 and t = 4

= 3x2000+4x1500 = 12,000

i. using the similar approach also s = 3 and t = 4

= 3x150 + 4x 90 = 810

no any other value for s and t satisfy the above constraoints...