7. You have $367.50 after two years.
Start by converting 2.5% into a decimal (divide by 100) and multiplying by 350 to find the rate of interest per year.
350(0.025) = 8.75
Since it's for two years, multiply by two.
8.75 x 2 = 17.5.
Add it on to he original, and we have
350 + 17.5 = 367. 5, or $367.50 when converted back to money.
8. The annual interest rate is 2.4%
find the interest rate per year:
120/2.5 = 48 dollars per year. this is the interest amount, we want to find the interest rate. To do this, find what % of 2000 that 48 is equal to.
Set up a system of equations and cross multiply.
2000x = 48(100) > 2000x = 4800
2000/2000x = 4800/2000 > x = 2.4
So, the interest rate is 2.4%.
9. the interest paid is $300 after six months, and $600 after a year.
Find the interest rate, similar to problem 7.
3000 x 0.2 = 600. This means the interest paid is $600 a year. In six months, the total will be half, or $300.
10. four years.
Find interest rate.
200(0.035) = $7/year
Remember that value. Subtract needed from current.
228 - 200 = $28.
So, we have an interest rate of $7 a year and we need $28. Normally, we'd solve using an expression, but in this case we can use simple multiplication. Knowing that 7 x 4 = 28, We can decide that it will take four years.