The salary scale for a clerical officer starts at Naira 1.1million per annum.a rise of 72000 is given at the end of each year. Find the total amount of money earned in 12years

Answer 1

To find the total amount of money earned in 12 years, we need to calculate the salary earned each year and then sum them up.

Initial salary = Naira 1,100,000 per annum
Annual increase = Naira 72,000

After 1 year: Naira 1,100,000 + Naira 72,000 = Naira 1,172,000
After 2 year: Naira 1,172,000 + Naira 72,000 = Naira 1,244,000
.
.
.
After 12 years: Naira 1,100,000 + 11(Naira 72,000) = Naira 2,004,000

Now, we can sum up the salary earned each year for 12 years:

Total amount earned in 12 years = Naira 1,100,000 + Naira 1,172,000 + Naira 1,244,000 + ... + Naira 2,004,000

This is an arithmetic series, and we can use the formula for the sum of an arithmetic series to find the total amount earned in 12 years:

Sum = n/2 [2a + (n-1)d]
where:
n = number of terms (12 years)
a = first term (Naira 1,100,000)
d = common difference (Naira 72,000)

Sum = 12/2 [2(1,100,000) + (12-1)(72,000)]
Sum = 6 [2,200,000 + 11(72,000)]
Sum = 6 [2,200,000 + 792,000]
Sum = 6 [2,992,000]
Sum = 17,952,000

Therefore, the total amount earned in 12 years is Naira 17,952,000.