Try the fastest way to create flashcards
Question

# A credit card promotion offers a discount on all purchases made with the card. The discount is directly proportional to the size of the purchase. If you save $1.35 on a$20 purchase, how much will you save on a \$173 purchase?

Solution

Verified
Step 1
1 of 2

The variation equation is

$d=ks$

where $k$ represents the constant of variation, $d$ is the discount and $s$ the size of the purchase.

First, find the constant of variation.

To find the constant of variation, substitute in the variation equation $1.35$ for $d$ and $20$ for $s$.

\begin{align*} 1.35&=k\cdot20&&\text{Divide both sides by 20.}\\ \dfrac{1.35}{20}&=k\\ k&=0.0675 \end{align*}

The constant of variation is $0.0675$.

Now, substitute in the variation equation $173$ for $s$ and $0.0675$ for $k$ to find $d$.

\begin{align*} d&=0.0675\cdot173\\ d&=11.6775 \end{align*}

You will save $\11.6775$ on a $\173$ purchase.

## Recommended textbook solutions

3rd EditionISBN: 9780076213924James Flanders
3,146 solutions

#### enVision Algebra 2

1st EditionISBN: 9780328931590 (1 more)Al Cuoco
3,573 solutions

#### Big Ideas Math Algebra 2: A Common Core Curriculum

1st EditionISBN: 9781608408405 (2 more)Boswell, Larson
5,067 solutions

#### Big Ideas Math: Algebra 2 A Common Core Curriculum

1st EditionISBN: 9781642088052Laurie Boswell, Ron Larson
5,066 solutions