Question

Which inequality models this problem? Miranda started a car-washing business. She spent $75 to purchase supplies to get started and she uses about $0.50 worth of supplies per car washed. Miranda charges $9 for each car washed. Let c represent the number of cars. What is the minimum number of cars Miranda will need to wash to make a profit? 9c>75+0.5c 0.5c>75+9c 9c<75+0.5c 0.5c?75+9c

Answer 1

Given

Miranda started a car-washing business

She spent $75 to purchase supplies to get started and she uses about $0.50 worth of supplies per car washed.

Miranda charges $9 for each car washed

Find out the minimum number of cars Miranda will need to wash to make a profit.

To proof

As given

let c represent the number of cars.

She spent to purchase supplies to get started = $ 75

she uses worth of supplies per car washed = $ 0.50

Miranda charges  for each car washed = $ 9

than the inequality be

$9c> 75+0.50c\\9c-0.50c>75\\8.5c> 75\\c> 8.8$

i.e the minimum number of cars  Miranda will need to wash to make a profit is 9 .

Hence proved