Question

Bob has some 10 lb weights and some 3 lb weights. Together, all his weights add up to 50 lbs. If x represents the number of 3 lb weights and y represents the number of 10 lb weights, which equation can be used to find the number of each type of weight Bob has?

Answer 1

Number of 3 lb weight = x

Number of 10 lb weight = y

Total weight = 50 lb

⇒3x + 10y = 50

To find the value of x:

3x + 10y = 50

3x = 50 - 10y

3x = 10( 5 - y)

x = 10(5-y) / 3

To find the value of y:

3x + 10y = 50

10y = 50 - 3x

y = (50 - 3x) / 10

Answer: x = 10(5-y)/3 and y = (50 - 3x)/10 are the two equations.

Answer 2

Total weight = 50 lb

3x + 10y = 50

find the value of x:

3x + 10y = 50

3x = 50 - 10y

x = 10(5-y) / 3

find the value of y:

3x + 10y = 50

10y = 50 - 3x

y = (50 - 3x) / 10