Question

Bill, Phil and Jenny are siblings. Bill is twice as old as Phil. Jenny is two years younger than Bill. Currently, their dad is twice as old

as the sun of their ages. In nine years, their dad's age will be equal to the sum of his three kids' ages at that time. What is Jenny's
current age?

Answer 1

as below

Explanation:

current ages

Bill is 8

Jenny is 6

and Phil is 4

the dad is 36

Answer 2

9514 1404 393

Answer:

6

Explanation:

Let p, b, j, d represent the ages of Phil, Bill, Jenny, and Dad. We are given the relations ...

b = 2p

j = b -2

2(p +b +j) = d

(p+9) +(b+9) +(j+9) = d+9

_____

Solving the last equation for d, we get ...

(p +b +j) +18 = d

Substituting for the sum of p, b, j in the third equation, we have ...

2(d -18) = d

d = 36 . . . . . . . . add 36-d

Substituting for b and j in the third equation, we get ...

2(p +(2p) +(2p-2)) = 36 . . . . . uses b=2p in the 2nd equation

10p -4 = 36 . . . . . . . . . . . . . . . collect terms

p = 40/10 = 4 . . . . . . add 4; divide by 10

b = 2p = 8

j = b -2 = 6

Jenny's current age is 6.

_____

All of the ages are ...

Bill: 8; Jenny: 6; Phil: 4; Dad: 36