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
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.