A savings account earns 8% interest each year, compounded quarterly (4 times a year). If a person invests $100 and make no further deposits or withdrawals, what is the balance in the account after 3 years

Solution:

The formula for compound interest, including principal sum, is:

Where,

A = the future value of the investment

P = the principal investment amount

r = the annual interest rate (decimal)

n = the number of times that interest is compounded per unit t

t = the time the money is invested

From given,

p = 100

t = 3 years

r = 8 % = 8/100 = 0.08

n = 4 times

Therefore,

Thus the balance in account after 3 years is $ 126.82

where is the figure

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads