Simple interest I=PRT Interest=Principal times Rate times Time principal=amount invested rate=rate in decimal t=time in years so they take the same time investment will be origianl+3% of it each time Len=5200+(5200 times 0.03 times t) Dave=3600+(3600 times 0.05 times t) so when will dave's investment be more than len's?
dave>len 3600+(3600 times 0.05 times t)>5200+(5200 times 0.03 times t) 3600+180t>5200+156t minus 156t both sides 3600+24t>5200 minus 3600 both sides 24t>1600 divide both sides by 24 t>66.6666666666666666666 so after 67 years
