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Question 1085039: 1)Joe wanted to purchase a new computer, so he invested $900 for 2 years. If he ended with an amount of $1100, what was the interest rate on joe's investment?
Please help me with this math questions along with the others
2) Jojo chooses to invest $20,000 for 4 years in a savings account, which offers an interest rate of 4%/yr. If the interest is compounded monthly, how much interest will jojo make after the 4 years?
3) George is investing in a savings account that offers an annual interest rate of 10% compounded weekly. What is the weekly rate of interest?
4) Determine the gross weekly income for the hours worked at a given rate. Overtime is double time for more than 36 hours worked. Bob works in a hat shop where he receives $450 a week plus 2.5% commission on the hats sold. Last week his hat sales totaled $12,500?
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website!
1)Joe wanted to purchase a new computer, so he invested $900 for 2 years. If he ended with an amount of $1100, what was the interest rate on joe's investment?
he invested 900 and has 1100 after 2 years.
if we assume compound interest, then f = p * (1+r) ^ n
f is the future value
p is the present value
r is the interest rate per time period
n is the number of time periods.
if we assume the interest was compounded yearly, then we would use the following formula.
1100 = 900 * (1+r) ^ 2
solve for (1+r)^2 to get (1+r)^2 = 1100/900 = 1.222.....
solve for (1+r) to get (1+r) = (1.222.....)^(1/2) = 1.105541597...
subtract 1 from that and multiply it by 100% to get 10.5541597..... percent.
that's an annual interest rate of approximately 10.55%.
2) Jojo chooses to invest $20,000 for 4 years in a savings account, which offers an interest rate of 4%/yr. If the interest is compounded monthly, how much interest will jojo make after the 4 years?
f = p * (1+r) ^ n
f is the future value
p is the present value
r is the interest rate per time period.
n is the number of time periods.
the interest rate is 4% per year compounded monthly.
divide 4% by 12 to get an interest rate of .333333......% per month.
divide that by 100 to get an interest rate of .0033333..... per month.
the investment is for 4 years.
since the interest rate is compounded monthly, multiply the number of years by 12 to get 48 months.
the formula becomes f = 20,000 * (1.0033333.....) ^ 48
solve for f go get f = 23,463.9734
round to 23,463.97
3) George is investing in a savings account that offers an annual interest rate of 10% compounded weekly. What is the weekly rate of interest?
there are 52 weeks in the year.
divide 10% per year by 52 to get .1923076925 percent per week.
4) Determine the gross weekly income for the hours worked at a given rate. Overtime is double time for more than 36 hours worked. Bob works in a hat shop where he receives $450 a week plus 2.5% commission on the hats sold. Last week his hat sales totaled $12,500?
he makes $450 a week plus 2.5% commission on value of hats sold.
last week he sold 12,500 in hats.
.025 * 12,500 = 312.5
he made 450 + 312.5 = 762.5 for the week.
this problem does not involve hours worked per week.
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