You invest $275.00 in a money-market account that pays simple interest at a rate of 10%. How long must you leave your investment in the money-market account if you expect to earn $27.50 in interest?
A year? How do I work it?
275 * 0.1 = $27.50
One year
What about this one?
A new house costs $160,000.00. Sara wants to buy the house and needs $1,534.00 for a down payment. If Sara currently has $1,300.00 in a savings account paying simple interest at a rate of 3%, how long must she keep the money in the savings account in order to have enough for the down payment on the house?
1,534 - 1,300 = $234 she needs
1,300 * 0.03 = 39
234 / 39 = 6 years
Thank you Ms. Sue, I really appreciate your help.... :-)
You're very welcome, Rawr!
A new house costs $160,000.00. Sara wants to buy the house and needs $1,534.00 for a down payment. If Sara currently has $1,300.00 in a savings account paying simple interest at a rate of 3%, how long must she keep the money in the savings account in order to have enough for the down payment on the house?
To calculate the time required to earn a certain amount of interest, you can use the formula for simple interest:
Interest = Principal × Rate × Time
In this case, the principal (amount invested) is $275, the rate is 10% (which can also be written as 0.10), and the interest earned is $27.50. You want to find out the time required, so you can rearrange the formula to solve for time:
Time = Interest / (Principal × Rate)
Plugging in the given values:
Time = $27.50 / ($275 × 0.10)
Simplifying further:
Time = $27.50 / $27.50
The interest and the amount invested are the same, so the answer is 1.
Therefore, you must leave your investment in the money-market account for 1 year to earn $27.50 in interest.