Ray's weight is 3 times the weight of his sister. His dad weighs twice as much as Ray. Their total weight is 400 pounds. How much does each person weigh?

1 answer

What does this problem teach you about physics? Nothing.

Use algebra.
R = Ray's weight
S = Sis' weight
D = Dad's weight

R = 3S
D = 2R = 6S

S + 3S + 6S = 10S = 400

Take it from there.