Problema Solution

Mary is 4 times as old as her brother Charlie.In four years, Mary will be twice as old as her brother.How old is Mary/ How old is Charlie.

Answer provided by our tutors

let 'x' represent the age of Charlie, then '4x' represents the age of Mary

Mary 4 years later is '(4x+4)' years old and Charlie will be '(x+4)' years old. 

May will be twice as old as Charlie in 4 years:

(4x+4)=2(x+4)

click here to solve for x

x=2

4*2=8

May is 8 years old, Charlie is 2 years old.