Question

Arnold is 10 yeras older than his brother richard. In 10 years richard will be 3/4as old aas arnold. how old is ecah one?

Answer 1

Richards current age : x
Arnold's current age : x+10

Richards age 10 years from now : x+10
Arnold's age 10 years from now: x+20

x+10 = 3/4(x+20)
solve for x

Answer 2

x+10 = 0.75 (x+20)
x+10 = 0.75x+15
0.25x+10 = 15
0.25x = 5
x = 20

"x" = 20
"x+10" = 30