You have to decide between two different companies that sell dirt. company a sells dirt for $137.5 for 50 square feet and has a delivery fee of $100 dollars. company b sells dirt for $15 for 5 square feet and offers free delivery. how much dirt do you need to buy for both companies to charge the same.

You need to buy 400 square feet of dirt for both companies to charge the same

Solution:

Given that,

Company A sells dirt for $137.5 for 50 square feet and has a delivery fee of $100 dollars

Dirt sold for $137.5 for 50 square feet

Let us find dirt sold for 1 square feet:

50 square feet = $ 137.5

1 square feet =

Thus dirt sold for $2.75 for 1 square feet

Company A has a delivery fee of $ 100 dollars

Amount Charged by company A:

Let "x" be the amount of dirt bought for 1 square feet

A = 2.75(x) + 100

A = 2.75x + 100 --- eqn 1

Company B sells dirt for $15 for 5 square feet and offers free delivery

Dirt sold for $ 15 for 5 square feet

5 square feet = $ 15

1 square feet =

Thus dirt sold for $ 3 for 1 square feet

Company B offers free delivery

Amount Charged by company B:

A = 3x  ---- eqn 2

Let us equate eqn 1 and eqn 2 to find the dirt you need to buy for both companies to charge the same

2.75x + 100 = 3x

3x - 2.75x = 100

0.25x = 100

x = 400

Thus you need to buy 400 square feet of dirt for both companies to charge the same

b.an increase in a causes b to decrease