Question

David invested $220 in a savings account that offers a 3% return on the investment. The value of David's investment will be at least $400 after a period of years. Hint: Use the formula A = P(1 + r)t, where A is the amount after t years, P is the amount invested, r is the rate of interest, and t is the time period. Use a calculator to compute the answer, and round it off to the nearest year.

Answer 1

400=220(1.03)^t
1.8181=1.03^t
ln 1.8181=ln 1.03^t=t ln 1.03
ln 1.8181/ln 1.03=t
t=20.225 years
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