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During three consecutive years, an employers salary is increased by 15%. If after three years his salary is 45,400, what was his salary before the raises?

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Answer:

$29,851.24

Explanation:

The salary started as x.

Each year it was increased 15%.

A full amount is 100% of the amount. When you add 15% to the amount, you now have 115% of the amount.

115% as a decimal is 1.15; that means that to increase an amount by 15%, multiply the amount by 1.15

For example, let's say you want to know what is a 15% increase on 100. Start with 100. 15% of 100 is 15, so if you add 15% to 100 you expect to get 115.

Now multiply 1.15 by 100. You also get 115 showing you that multiplying a number by 1.15 is the same as adding 15%.

Now let's get back to our problem.

The salary started as x.

Each year, the increase in salary was 15% of the previous salary.

After 1 year the salary is 1.15x.

After 2 years, the salary is 1.15(1.15x).

After 3 years, the salary is 1.15(1.15(1.15x)) = (1.15^3)x

We are told that the salary became $45,400 after the three 15% increases, so

(1.15)^3 * x = 45,400

Multiply out 1.15^3 as 1/15 * 1.15 * 1.15 = 1.520875

1.520875x = 45,400

Divide both sides by 1.520875.

x = 45,400/1.520875

x = 29,851.24

Answer: $29,851.24

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