Question

Introduce variables to represent items of interest in the problem. For

example, (1) Let n be the number to be found, or (2) Let a be Alice’s

current age, or (3) Let r be the rate of the first car.

(2)

Write down an equation using the information given in the problem. This

is the really important part for this particular assignment!

(3)

Solve the equation and find the value requested in the problem.

Al is 15 years older than Sal. In ten years Al will be twice as old

as Sal. How old are they now?

Adam is twice as old as Sue. In ten years the sum of their ages

will be 50. How old are they now?

Amy is six years older than Sam. Ten years ago the sum of their

ages was 16. How old are they now?

Answer 1

Al is 15 years older than Sal. In ten years Al will be twice as old as Sal. How old are they now?

Soln :
Sal's present age = s
So, Al's present age = s + 15

In 10 yrs time, their ages are :
s + 10 and s + 25

And we have
s + 25 = 2(s + 10)
s + 25 = 2s + 20
s = 5

So, present age of Sal= 5
And present age of Al = 5+15 = 20

-------------------------------------------------------------

2)
Sue's present age = s
So, Adam's present age = 2s

In 10 yrs their ages are :
s + 10 and 2s + 10

So,
s+ 10 + 2s + 10 = 50

3s = 30

s = 10

So, Sue's present age = 10
And Adam's present age = 20

-----------------------------------------------------------------

Sam's present age = s
Amy's present age = s + 6

10 yrs ago ages qere
Sam = s - 10
Amy = s + 6 - 10 = s - 4

s - 10 + s - 4 = 16

2s= 30

s = 15

Sam's present age = 15
Amy's present age = 21