A man’s salary increases by Ghȼ800.00 each

Question

year. If his total salary at the end of 12 years in
Ghȼ1,852,800.00. Find his initial salary in the
twelfth year.
A. Ghȼ15,000,000.00
B. Ghȼ1,500,000.00
C. Ghȼ150,000.00
D. Ghȼ15,000.00

Answer 1

Let the man's initial salary be x.

After one year, his salary will be x + 800.
After two years, his salary will be x + 2(800) = x + 1600.
Similarly, after 12 years, his salary will be x + 12(800) = x + 9600.

We are given that the total salary at the end of 12 years is Ghȼ1,852,800. So, we can write:

x + (x+800) + (x+1600) + ... + (x+9600) = 1,852,800

Simplifying this, we get:

12x + 800(1+2+...+12) = 1,852,800

12x + 800(78) = 1,852,800

12x = 1,852,800 - 62,400

12x = 1,790,400

x = 149,200

Therefore, the man's initial salary in the twelfth year (i.e. after 11 salary increases of Ghȼ800 each) was Ghȼ149,200.

Answer: C. Ghȼ150,000.00