Question

You've been saving $8.50 each week to buy a bicycle from your local bike store. The bike originally cost $210, but is on sale for 25% off. So far, you have saved $120 for your purchase. How many more weeks must you save up to have enough money to buy the bike?

Answer 1

5 weeks

Explanation:

First, you must calculate what 25% off from $210 is. Since 100 - 25% = 75%, the price of the bike is 75% of $210.

`(x)/(210)=(75)/(100)`

`100 * x = 75 * 210`

`100x = 15750`

x = $157.50

Then, make an equation that represents the money needed to save up for the bike.

y = mx + b

bike's price = (money earned each week)(number of weeks) + money saved

157.5 = 8.50x + 120

157.5 - 120 = 8.50x + 120 - 120

37.5/8.5 = 8.5x/8.5

x = 4.4117

You need to round 4.4 to 5 because number of weeks must be whole numbers