Maria invested $4,000 at 3.5% simple interest. she left the principal invested for 57 months. robert invested $3,500 at 8.5% simple interest. he left the principal invested for 42 months. how much more total money did maria have than robert at the end of their investments

Maria have $123,75 more total money than Robert at the end of their investments.

Step-by-step explanation:

To calculate the simple interest we should multiply the Initial invest, with the interest without percentage and the time in years.

As the time is in months we have to divide it by 12 so we have the mesure of time in years, then the interest for each of the investments will be:

Maria

Invest = $4,000 Interest = 3.5/100=0.035  Time = 57/12 = 4.75

Simple Interest = 4,000 x 0.035 x 4.75 = $665

Total money at the end of the invest = $4,000 + $665 = $4,665

Robert

Invest = $3,500 Interest = 8.5/100=0.085  Time = 42/12 = 3.5

Simple Interest = 3,500 x 0.085 x 3.5 = $1,041.25

Total money at the end of the invest = $3,500 + $1,041.25 = $4,541.25

Now we have to subtract the total money of Robert from the total money of Maria to know how much money did she got over Robert after their invests

$4,665 - $4,541.25 = $123.75

At the end of the invest, Maria got $123,75 more than Robert