Answer: 4
Step-by-step explanation:
Let P represent Pete's age today. Let C represent Claire's age today.
2 years ago: P - 2 = 3(C - 2) ⇒ P - 2 = 3C - 6 ⇒ P = 3C - 4
4 years ago: P - 4 = 4(C - 4) ⇒ P - 4 = 4C - 16 ⇒ P = 4C - 12
Use substitution to solve the system above:
3C - 4 = 4C - 12
- 4 = C - 12
8 = C
Plug in the C-value above into one of the equations to solve for P:
P = 3C - 4
= 3(8) - 4
= 24 - 4
= 20
So, Pete is 20 yrs old today and Claire is 8 years old today
When will Pete be twice as old as Claire?
20 + x = 2(8 + x)
20 + x = 16 + 2x
20 = 16 + x
4 = x
Their ages will have a 2:1 ratio in 4 years.
