Question

Joe has $1,800 from his summer job to invest. If joe wants to have $2,340 altogether and invests the money at 5% simple interest, in how many years will Joe have $2,340?

Answer 1

1800*1.05^x = 2340
so use logarithms. 2340/1800 = 1.05^x
log(2340/1800) = x log(1.05)
log(2340/1800)/log(1.05) = x = 5.38 (3sf)