Question

Dawn, Keith, and John are all working on a history project. Dawn spent 1.5 hours less than 5 times as many hours on the project as John did. Keith spent 1.2 hours more than 4 times as many hours on the project as John did. If Dawn and Keith spent the same amount of time working on the project, how many hours did John spend working on the project?

Answer 1

John spent 2.7 hours

Explanation:

John will be (z)

Dawn has spent 5z-1.5

Keith has spent 4z+1.2

5z-1.5=4z+1.2

+1.5 +1.5

5z = 4z+2.7

-4z -4z

z = 2.7

Answer 2

John spent 2.7 hours working on the project.

Explanation:

Dawn: 5x-1.5 with x representing the number of hours John spent

Keith: 4x+1.2

If Dawn and Keith spent equal time then these 2 equations equal each other then solve for x.

5x-1.5=4x+1.2

5x-4x=1.2+1.5

x=2.7