Mario borrows $4800 for 8.5 years at a fixed rate of simple interest. at the end of that time, he owes $8000. what interest rate is he being charged?

Step-by-step explanation

The unknown is the interest rate.

The givens are the principal=$4800, time=8.5 years and amount=$8000(to find the interest, subtract the principal from the amount,$8000-$4800=$3200)so interest is $3200

The formula for finding rate is R=I*100/PT where R is rate, I is interest and P is principal and T is time.the 100 is there because R is a percentage.

R=$3200*100/$4800*8.5=7.8%(rounded to nearest tenth)

Therefore the interest rate is about 7.8%

range =5

step-by-step explanation:

to find the range, we take the largest value and subtract the smallest value.

the largest value is 5

the smallest value is 0

the range is 5-0   =5