Need Help Plz (1 Viewer)

[B737NGX]

What is the best method of solving this kind of problem???

James’s grandmother was 45 when James was born. She was four times his age when she retired. How old was James when his grandmother retired?

 

[dangerouss]

Algebraic method (simultaneous eqns):
James' grandmother was 45 when he was born - (assume G is grandmother and J is James) from that information:
G = 45 + J

And

She was 4 times his age when she retired (at retirement):

4J = G

Substitute 2nd eqn into 1st:

4J = 45 + J
3J = 45
J = 15

Sub J = 15 in 1st (solve for G)

G = 45 + J
G = 45 + 15 = 60

Therefore, James was 15 when his grandmother retired at 60 years old.

 

[B737NGX]

thx buddy