Ann is 12 years old. Her mother is 3 times as old as Ann. How many years ago was her mother 4 times as old as Ann?

2 Answers
May 11, 2018

4 years ago

Explanation:

If we call Ann´s age A and mother´s age M:

A = 12

A * 3 = M

, a few years back ( Y ):

( A - Y ) * 4 = ( M - Y )

So, by substitution:

( A - Y ) * 4 = ( A * 3 - Y )

4A - 4Y = 3A - Y

4A - 3A = 4Y - Y

A = 3Y

Y = A/3 = 12/3= 4

May 11, 2018

4 years ago.

Explanation:

We know both of their present ages.

If Ann is 12 years old, then her mother is 3xx 12=36 years old.

A number of years ago,they were both younger.
Let the number of years be x.

Ann's age was 12-x and her mother's age was 36-x

36-x =4(12-x)" "larr the mom was 4 times older,

36-x = 48-4x

4x-x = 48-36

3x = 12

x=4

It was 4 years ago.

Check: Ann was 8 and her mom was 32

4 xx8 = 32