you need
2000 * 1.10^t = 2662
1.10^t = 1.331
t log1.10 = log1.331
t = log1.331 / log1.10 = 3 years
Trying to help my 8th grader, but I'm at a loss with this one. Can anyone assist? Thank you.
Gwyneth placed $2,000 in an account that warned 10% interest, compounded annually. How many years did she save if she if she had $2,662 in her account?
3 answers
2000(1.10)^n = 2662
Kind of hard to believe that this is grade 8 question since it
requires logs to actually solve it, .... anyway ...
1.1^n = 1.331
take logs of both side, and using log rules
n log 1.1 = log 1.331
n = log1.331/log1.1 = 3
ok,
perhaps they were expected to do it this way
after 1 year, amount = 2000(1.1) = 2200
after 2 years, amount = 2200(1.1) = 2420
after 3 years, amount = 2420(1.1) = 2662
well, that was lucky!
Kind of hard to believe that this is grade 8 question since it
requires logs to actually solve it, .... anyway ...
1.1^n = 1.331
take logs of both side, and using log rules
n log 1.1 = log 1.331
n = log1.331/log1.1 = 3
ok,
perhaps they were expected to do it this way
after 1 year, amount = 2000(1.1) = 2200
after 2 years, amount = 2200(1.1) = 2420
after 3 years, amount = 2420(1.1) = 2662
well, that was lucky!
I wouldn't have solved it. Thank you!!
1 answer