Question

In 18 years time Halley will be five times as old as she was two years ago. Write this information in the form of an equation involving Halley's present age, a years How old is Halley now?

Answer 1

To solve any questions relating to ages, I find it easier to make a table, like in the picture below.

See picture for answer and clear diagram.

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Notes/Explanations + answer in written form

Let's say that Halley's age now is: x

That means that her age in 18 years is: x + 18

It also means that her age 2 years ago is: x - 2

In the question, we are told that when Halley is 18 years older that her current age, she will be 5 times the age she was when she was 2 years younger than her current age

That means:

Halley's current age + 18 years = 5 times (Halley's current age - 2 years)

So we get this equation (which we solve to get the answer) :

x + 18 = 5 * (x -2) ( expand the brackets)

x + 18 = 5x - 10 (subtract x from both sides)

18 = 4x - 10 (add 10 to both sides)

28 = 4x (now divide both sides by 4)

7 = x

Therefore, Halley's current age is 7 years