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

total weight = 50 lb
x = number of 3-lb weights
y = number of 10-lb weights

weight of 3-lb weights = 3x
weight of 10-lb weights = 10y
total weight = 3x + 10y

equation
3x + 10y = 50