# Math [Interest]

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Okay, so I've been away from school for three weeks, and we have a math test tomorrow. I only just found out, and my friend emailed me the review questions. If someone could help me out, and show me how to do this, I'd appreciate it. No, I do not want someone to do my homework for me. I'm an idiot where math is concerned and I don't understand this.

1. Julie invests \$500 at 5% simple interest. How long will it take to double in value?

2. Helen won the lotto when she was 18 and invested all the money at 4.5% compounding annually. When she was 24 it was worth \$145073. How much did she win in the lotto?

3. Jessica has \$150000 to invest for three years. She researches three investment options. Calculate the interest each option would earn and select the best option.
a. 5% pa simple interest

b. 4.5% pa compounding monthly

c. 4.25% pa compounding annually

4. Calculate the interest earned for the month in this cash management account.

Account Balance | Interest Rate
> \$30000 | 3.5%
\$30000-\$15000 | 2.95%
\$15000-\$5001 | 2.5%
\$5000-\$501 | 1.25%
\$500 and under | 0.5%

Date | Transaction | Balance
1 April | Opening Balance | \$24903.25
15 April | Deposit \$13500 | \$38403.25
23 April | Withdraw \$30000 | \$8403.25

• Math [Interest] - ,

I'll try similar problems as the first two.

1. 10000 dollars at 4% interest would give 10000*4% = 10000*4/100=\$400 per year.
To double, it would take 10000/400 = 25 years.

2. \$1000 at 5% compound interest (compounded yearly) would give me in 5 years \$1000*1.055 = \$1276.28.

If I received \$4000 at the end of 5 years, I won (5 years ago, by proportions) \$4000*(1000/1276.28)=\$3134.10.

Give a try for #1 and #2 and the rest, and post what you've got. We'd be glad to help.