Question

Bob has some 10 pound weights and some 3 pound weights together all his ways add up to 50 pounds if X represents the number 3 pound weights and Y represents the number 10 pound weight which equation can be used to find the number of each type of weight bob has

Answer 1

No. of 3 pound weights = (10X + 10Y - 50) / 7

No. of 10 pound weights = (X + Y) - [ (10X + 10Y - 50) / 7 ]

Explanation:

Assuming all are 10 pound weights

Total mass of weights = 10 (X + Y) = 10X + 10Y

Difference in assumed mass and actual mass = 10X + 10Y - 50

Difference in mass of each type of weight = 10 - 3 = 7

No. of 3 pound weights = (10X + 10Y - 50) / 7

No. of 10 pound weights = (X + Y) - [ (10X + 10Y - 50) / 7 ]