the annual salary of a clerk in 1998 was rs.10800. It was increased by15% in 1989 and again by 15% in 1990. What was his salary in 1990
10800 * 1.15 * 1.15 = ?
To find the clerk's salary in 1990, we need to calculate the cumulative increase of 15% in 1989 and another 15% increase in 1990.
Step 1: Calculate the increase in 1989:
Increase = (15/100) * Salary in 1988
Given the salary in 1998 is Rs. 10800, the Salary in 1988 for a clerk can be found by the compound interest formula:
Cost Price = (Selling Price) / (1 + Increase %)
Let's calculate the Salary in 1988 (SP):
SP = 10800 / (1 + 0.15) = 10800 / 1.15 ≈ 9391.30
Step 2: Calculate the increase in 1989:
Increase = (15/100) * 9391.30 ≈ 1408.70
To find the salary in 1989:
Salary in 1989 = Salary in 1988 + Increase
Salary in 1989 = 9391.30 + 1408.70 = 10800
Step 3: Calculate the increase in 1990:
Increase = (15/100) * Salary in 1989
Increase = (15/100) * 10800 = 1620
To find the salary in 1990:
Salary in 1990 = Salary in 1989 + Increase
Salary in 1990 = 10800 + 1620 = 12420
Therefore, the clerk's salary in 1990 was Rs. 12420.