~ 6.12 ~

Learning Targets

• I can solve story problems about percent increase or decrease by drawing and reasoning about a tape diagram or by writing and solving an equation.

We can solve problems where there is a percent increase or decrease by using what we know about equations. For example, a camping store increases the price of a tent by 25%. A customer then uses a $10 coupon for the tent and pays $152.50. We can draw a diagram that shows first the 25% increase and then the $10 coupon.

The price after the 25% increase is p + .25p or 1.25p. An equation that represents the situation could be 1.25p - 10 = 152.50. To find the original price before the increase and discount, we can add 10 to each side and divide each side by 1.25, resulting in p = 130. The original price of the tent was $130.

An item costs x dollars and then a 20% discount is applied. Select all the expressions that could represent the price of the item after the discount.

1. A store is having a sale where all shoes are discounted by 20%. Diego has a coupon for $3 off of the regular price for one pair of shoes. The store first applies the coupon and then takes 20% off of the reduced price. If Diego pays $18.40 for a pair of shoes, what was their original price before the sale and without the coupon?

2. Before the sale, the store had 100 pairs of flip flops in stock. After selling some, they notice that ⅗ of the flip flops they have left are blue. If the store has 39 pairs of blue flip flops, how many pairs of flip flops (any color) have they sold?

3. When the store had sold 2/9 of the boots that were on display, they brought out another 34 pairs from the stock room. If that gave them 174 pairs of boots out, how many pairs were on display originally?

4. On the morning of the sale, the store donated 50 pairs of shoes to a homeless shelter. Then they sold 64% of their remaining inventory during the sale. If the store had 288 pairs after the donation and the sale, how many pairs of shoes did they have at the start?