An algebra problem by Vinamr Kanodia

Algebra Level 2

The age of a man is 4 times that of his son. Five years ago , the man was nine times as old as his son was at that time. The present age of the man is ?


The answer is 32.

Vinamr Kanodia by Vinamr Kanodia , 19, India

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Let m m and s s be the present ages of the man and his son, respectively.

m = 4 s m=4s or s = m 4 s=\dfrac{m}{4} ( 1 ) \color{plum}(1)

m − 5 = 9 ( s − 5 ) m-5=9(s-5) ( 2 ) \color{plum}(2)

Substitute ( 1 ) \color{plum}(1) in ( 2 ) \color{plum}(2) .

m − 5 = 9 ( m 4 − 5 ) m-5=9\left(\dfrac{m}{4}-5\right)

m − 5 = 9 4 m − 45 m-5=\dfrac{9}{4}m-45

9 4 m − m = 45 − 5 \dfrac{9}{4}m-m=45-5

m = 32 m=32

0 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...