Question

Five years ago, Mark was twice as old as Max. In three years, Max's age will be 2/3 that of Mark. What is the sum of their ages now

Answer 1

Answer:

4years

Step-by-step explanation:

Let the present age of Mark be x

Let the present age of Max be y

Five years ago

Mark = x-5

Max = y - 5

If mark was twice as old as Max, then;

x - 5 = 2(y-5)

x-5 = 2y - 10

x-2y = -10+5

x - 2y = -5 ... 1

In three years,

mark = x+3

Max = y+3

Now if Max's age will be 2/3 that of Mark, then;

x+3 = 2/3(y+3)

3(x+3) = 2(y+3)

3x + 9 = 2y+6

3x-2y = -3 .... 2

Solve 1 and 2 simultaneously

x - 2y = -5 ... 1

3x-2y = -3 .... 2

From 1: x = -5 + 2y

Substitute into 2:

3(-5+2y) - 2y = -3

-15 + 6y - 2y = -3

-15 + 4y = -3

4y = -3 + 15

4y = 12

y = 3

Recall thet x = -5+2y

x = -5+2(3)

x = -5 + 6

x = 1

The sum of their ages will be x+y

x+y = 1+3

x+y = 4

Hence the sum of their ages now is 4years