Percentages- help in Maths?

Question

Find the simple interest earned on $15000 if the rate is:
a. 5.6% p.a. for 3years
b. 4.25% p.a. for 7months

Answer 1

a. ($15000 x 0.056) x 3 = $2520

b. (15000 x 0.0425) x 7/12 = $371.875

Answer 2

remember the formula:
a= p(r)/100 (n)
a = amount of interest
p = principal
r - rate
n = number of periods taken...let's try..
a = 15000(5.6)/100 (3)
a = $2520
this will be the simple interest earned.. @ 5.6% for 3 years

b. again:
a = 15000(4.25/100) (7/12) = because an annum = 1 year
so if it's less than a year, you have to get the length by dividing the current to the total number of months..
so:
a = $371.875
for 7 months..

hope this helps!

Answer 3

a) Simple Interest : PRT/100

So, ($15000*5.6*3)/100 = $2520


b) Using the same formula BUT this time you need to convert the 7 months into year units. That is >>> (7/12) year (1 year consists of 12 months)

So, applying the formula and you get:

[$15000*4.25*(7/12)]/100 =$371.875 --($371.88)

=)

Answer 4

a. before I can solve this I need to know how often interest is CREDITED, and then I can calculate interest on the posted interest over the three years of the deposit, assuming NO withdrawals of interest.

b. same answer as part a--cannot calculate until I know how often interest is credited. For example, if interest is credited MONTHLY, would have to calculate one month's interest, add to principal, calculate month two on original principal plus first month's interest, etc for seven months.