Marshall, who is currently 20 years old, is 4 times as old as his brother Stephen. How old will Stephen be when he is half a old as Marshall?

Question

please help me im confused

Answer 1

M=20 S=20/4=5

Let x = number of years until Stephen is half Marshall's age

M+x=2(S+x)

20+x=2(5)+2x

10=x

S+x=5+10=15 years old when his older brother is twice his age.