Question

Usually, Johnny takes s minutes to get to school. However, during the last week, the traffic pattern changed. Johnny noticed that each day, he made it to school 3 minutes faster than the previous day. On the Friday, he got there in half the time of the previous day. Write an algebraic expression that shows how many minutes Johnny spent travelling to school from Monday to Friday.Simplify the expression completely.List the terms in your expression.For each term, identify the coefficient and variable.

Answer 1

$\frac{9s-9}{2}-18$

coefficient: 9 the variable s

1) Let's sketch out a diagram for that, given that Johnny notice that each day the speed of the traffic was getting faster and faster:

$\begin{gathered} M:s \\ T:s-3 \\ W:s-3-3=s-6 \\ Thu:s-9 \\ Fri:\frac{s-9}{2} \end{gathered}$

Note that on Friday, he came to school half the time he made it on Thursday.

2) So, we can write out the following expression:

$\begin{gathered} s+s-3+s-6+s-9+\frac{s-9}{2} \\ 4s-3-6-9+\frac{s-9}{2} \\ 4s-18+\frac{s-9}{2} \\ \frac{9s-9}{2}-18 \end{gathered}$

3) In this expression, we can tell the coefficient: 9 the variable s the constant is -18.