# math,algebra

posted by on .

Can someone help me put this into equations where i can solve them thanks.

Problem #1
Allen bought 20 stamps at the post office in 37cents and 20cents denominations. If the total cost of the stamps was \$7.06, how many 37cents stamps did Allen buy?

Problem #2
An 800g solution of acid and water contains 128g of acid. What percent of the solution is acid?

Problem#3
A principle of \$5000 was invested in a savings account for 4years. If the interest earned for the period was \$400, what was the interest rate per year?

Problem#4

Enrique puts 12% of his monthly paycheck in an IRA. If he invests \$72 in his IRA, how much was his paycheck?

1) I can't figure this one out

2) 128 is what percent of 800? Now write that in math terms (is means equals, of means multiply):
128=x(800)
Remember to multiply by 100 at the end because the decimal needs to be in percent form.

3) Principle = Rate x Time
5000=r(4)

4) \$72 is 12% of what? The what is the paycheck amount:
72=(0.12)(x)

belinda, thank you for helping me out

now for # 2

what i got was 16 is that correct so then it would just be 16%

#3

how can be 5000=r(4) where does the 400 goes?

#4

i get a crazy number with decimals. i get 14.46