Jen has eight dollars and Heather has 3/5 of the bill. How much did heather pay

3/5 is equal to 60%

so if 40% is 8 dollars then heather pays 12 and the total is 20

Let

Total Bill = $x

Given

Jen paid = $8

Heather paid = x (3/5) = $3x/5

Total Bill=Jen Paid + Heather Paid

x=8+3x/5

Multiply by 5 both sides

5x=40+3x

5x-3x=40

2x=40

2x/2=40/2

x=20

3/5 of 20 = (3/5) (20) = 3*4 = 12

Bill was for $20 Jen paid $8 and remaining $12 paid by Heather.