Luciano Webster

2022-07-28

Jack invests $1000 at a certain annual interest rate, and he invests another$2000 at an annual rate that is one-half percent higher. If he receives a total of $190 interest in one year, at what rate is the$1000 invested?

Kendrick Jacobs

Expert

Jack invests $1000 at a certain annual interest rate, and heinvests another$2000 at an annual rate that is one-half percenthigher.
If he receives a total of $190 interest in one year, atwhat rate is the$1000 invested?
using Interest = Principle x rate x time or I=PRT
x = 1st interest rate
x+.005 =2nd interest rate
time = 1 since it's 1 year so that drops out of the equation
1000x= interest for 1st amount
2000(x+.005) = interest for 2nd amount
1000x+2000(x+.005)=190
multiply
1000x+2000x+10=190
combine like terms
3000x+10=190
subtract 10 from each side
3000x=180
divide both sides by 3000
x=.06=6%
the \$1000 was invested at 6% interest
to check
does
1000(.06)+2000(.065)=190
60+130=190
190=190 yes

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