Chapter 9.6, Problem 27STP

To determine

Tofind: thegoals made by Tyra.

Answer to Problem 27STP

Tyra made $12$ goals.

Explanation of Solution

Given information:

Tyra made four times as many goals as Kailey and Kailey made nine fewer goals than Tyra.

Calculation: to find the goals made by Tyra, let $x$ represents the goals made by Kailey and $y$ represents the goals made by Tyra.

Since, Tyra made four times as many goals as Kailey so the equation must be,

  $y=4x$

And Kailey made nine fewer goals than Tyra.

  $x=y-9$

Now, solve the both equations,

  $\begin{array}{l}y=4x\text{ [}eq.1]\\ x=y-9\text{ [}eq.2]\\ y=4\left(y-9\right)\text{ [substitute from eq}\text{. 1]}\\ y=4y-36\text{ [multiply]}\\ 3y=36\text{ [simplify]}\\ y=12\text{ [diivide]}\end{array}$

Thus, the goals made by Tyra is $12$ .