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You put $400 in an account. The account earns $18 simple interest in 9 months. What is the annual interest rate?

User Arst
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1 Answer

6 votes
I=PRT
Interest=Principal times Rate time Time
time is in years and rate is in decimal

I=18
P=400
T= 9/12=3/4=0.75
R=?


18=400*R*0.75
18=300*R
divide both sides by 300
0.06=R

rate is 6%
User Timebandit
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