# Question 51db4

##### 2 Answers
Nov 22, 2017

Christianson is 18 years old and Yroak is 12 years old.

#### Explanation:

$C$ : Present age of Christianson,
$Y$ : Present age of Yroak,

Christianson is now 6 years less than twice the age of Yroak.

$C = 2 Y - 6$ ...... (1)

At 9 years age, Christianson was 3 times as old as Yroak. This means Yroak was 3 years old then. Let us assume that this was $X$ years from the present.

C = 9 + X; \qquad Y = 3 + X \qquad \rightarrow X = Y - 3;
Eliminate $X$ in one equation using the other
$C = 9 + \left(Y - 3\right) = 6 + Y$ ...... (2)

Comparing (1) and (2)
2Y - 6 = 6 + Y; \qquad \rightarrow Y = 12#

Therfore, $C = 2 Y - 6 = 18$

Nov 22, 2017

Please see answers and steps below...

#### Explanation:

Let yroak's age be $= x$

Hence we will used yroak age as the basis, to interpret the rest statement..

Christianson is now $6 y r s$ less than twice the age of yroak..

$6 y r s$ less means $\left(x - 6\right) y r s$ where $x$ is yroak's age

Bu since yroak's age was twice, hence the expression is;

Expression: $\left(2 x - 6\right) y r s$

Is it nine years ago or nine years after???

Well I'll interpret it separately..

Christianson was 3 times as old as yroak

If its' For Nine years ago

yroak's age $= x - 9$

Christianson's age $= 3 \left(2 x - 6\right) - 9$

If its' For Nine years after

yroak's age $= x + 9$

Christianson's age $= 3 \left(2 x - 6\right) + 9$

Remember yroak's age still remains unknown $x$, so we are using Christianson's age to find yroak's age..

We will equate both ages together...

$x - 9 = 3 \left(2 x - 6\right) - 9 \to$ For $9 y r s$ ago!

Expanding the brackets..

$x - 9 = 6 x - 18 - 9$

Simplifying..

$x - 9 = 6 x - 27$

Collecting like terms..

$x - 6 x = - 27 + 9$

$- 5 x = - 18$

$\cancel{-} 5 x = \cancel{-} 18$

$x = \frac{18}{5}$

$x = 4 y r s$ "which is not possible.."

$x + 9 = 3 \left(2 x - 6\right) + 9 \to$ For $9 y r s$ after!

Expanding the bracket..

$x + 9 = 6 x - 18 + 9$

Simplifying..

$x + 9 = 6 x + 9$

$x + \cancel{9} = 6 x + \cancel{9}$ "which is also not possible..

Please rephrased the statement!