SOLUTION: Jarvis invested some money at 5% interest. Jarvis also invested $152 more than 3 times that amount at 10%. How much is invested at each rate if Jarvis received $1387.90 in interest

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Question 1076283: Jarvis invested some money at 5% interest. Jarvis also invested $152 more than 3 times that amount at 10%. How much is invested at each rate if Jarvis received $1387.90 in interest after one year?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
total interest is 1387.90.

x = amount invested at 5%.

y = amount invested at 10%.

since the amount he invested at 10% is 152 more than 3 times the amount he invested at 5%, then:

y = 3 * x + + 152.

your formula for interest is:

.05 * x + .10 * y = 1387.90

since y = 3 * x + 152, replace it in this equation to get:

.05 * x + .10 * (3 * x + 152) = 1387.90

simplify to get:

.05 * x + .3 * x + 15.2 = 1387.90

combine like terms to get:

.35 * x + 15.2 = 1387.90

subtract 15.2 from both sides of the equation to get:

.35 * x = 1372.7

solve for x to get x = 1372.7 / .35 = 3922

since y = 3 * x + 152, then:

y = 11918

.05 * 3922 + .10 * 11918 = 1387.9

i believe that satisfies the problem statement.

your solution is that he invested 3922 at 5% and 11918 at 10%.