Billy is 40 years older than his daughter. 8 years from now, his daughter will be ¹₂ of his age while his niece will be ²₅ of his daughter. Express his niece’s present age as a fraction of Billy's present age. Leave your answer in its simplest form.

	Billy	Billy's daughter	Billy's niece	Difference between Billy and Billy's daughter
Before	10 u - 8	5 u - 8	2 u - 8	40
Change	+ 8	+ 8	+ 8
After	2x5	1x5
		5x1	2x1
Comparing Billy, his daughter and his niece in the end	10 u	5 u	2 u	5 u

The repeated identity is the age of Billy's daughter. LCM of 1 and 5 is 5.

The difference in age between Billy and Billy's daughter remains unchanged.

Difference in age between Billy and Billy's daughter
= 10 u - 5 u 
= 5 u 

5 u = 40

1 u = 40 ÷ 5 = 8

His niece's present age 
= 2 u - 8
= 2 x 8 - 8
= 16 - 8
= 8

Billy's present age
= 10 u - 8
= 10 x 8 - 8
= 80 - 8
= 72

His niece's present age as a fraction of Billy's present age
= ⁸₇₂
= ¹₉

Answer(s): ¹₉