Question

Rhea’s mother is four times as old as she is now. In twenty years the mother will be twice as old as her daughter. Find their present ages.

Answer 1

Answer:

Rhea's age = 10 , Mother's age = 40

Step-by-step explanation

Rhea's age = x

Mother's age = 4x

4x + 20 = 2(20 + x)

2x = 20

x = 10

Answer 2

Step-by-step explanation:

let Rhea's age be= R

Then Rehas mother = 4R

EQUATION

$4r = r \\ 20 + 4r = r + 20$

Instead of Multiplying mother with 2, we will multiply with daughter to make LHS=RHS

$20 + 4r = (r + 20)2 \\ 20 + 4r = 2r + 40 \\ 4r - 2r = 40 - 20 \\ 2r = 20 \\ r = 20 \div 2 \\ r = 10$

hence, Rehas present age = 10 years

and mother= 4r= 4*10 = 40 years