Answers

2014-11-05T15:48:13+08:00
Simple math.

Let's convert this first to math expression

K will be Kristyn and M for Mario

Let's do the first one.

Kristyn is 4 years younger than Mario

That will be like this

K = M - 4

Next, let's do the last one.

Three years from now, she will be 2/3 as old as Mario

That will be

(K + 3) = (2/3)M

Subtitute the first expression to the next one

M - 4 + 3 = 2/3(M + 3)

M - 1 = 2/3(M + 3)

M - 1 = 2/3M + 2

Multiply by 3 to eliminate fraction

3(M - 1) = 3(2/3M + 2)

3M - 3 = 2M + 6

Move 3 to the right and change sign and so as the 2M to the left

3M - 2M = 3 + 6

M = 9

Therefore:

Mario is 9

Let's solve for Kristyn

K = 9 - 4

K = 5

and Kristyn is 5

Let's check if adding 3 will make it 2/3

9 + 3 = 12

and

5 + 3 = 8

8/12 = 2/3 correct

I hope it helps.


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