Answer:
$14
Step-by-step explanation:
80% of $70 is $14, saving him $56
<span>5999382000 is the answer</span>
Total of $7.75
13 more quarters than nickels
15 nickels = $0.75
28 quarters = $7.00
28 - 15 = 13 coins
$7.00 + $0.75 = $7.75
She has 15 nickels and 28 quarters.
That would be written as:

And the step-by-step equation would be:
→ we take the 2 to the right side of the equation and do the IO*
→we solve for 
→ final answer
*Ps - IO is not an existing term and stands for inverse operation. In this case, because when we take to 2 to the right side of the equation (the 2 is a power) it'll have to turn into a square root (because exponents and roots are inverse operations)
Hope it helped,
BioTeacher101