Algebra solving problems

Question

Suppose that an account earns 5.3% interest and after 3 years the balance is $2318. Find the principal that was invested using B=P+Prt

Answer 1

B=P+Prt = P(1+rt)

2318 = P(1+.053(3)) = P(1.159)

P = 2318/1.159 = $2,000

the problem assumes simple interest with no compounding

in one year the interest = 2,000 x .053 = 106

for three years the interest =3x106 =318

total interest = $318

that plus the $2000 principle= 318+2000 = $2,318 balance after 3 years at 5.3% simple interest