Question

Erika’s toy ski chalet is valued at €450. Its value increases by 10% then decreases by 10% the year after. What is the value of Erika’s toy after these two changes?

Answer 1

€445.5

Explanation:

First we calculate the increase percentage and the increase.

Increase = 450 + (10%*450)

Now we must calculate the percentage of the increase.

Increase percentage = 10% of €450 = 450*0.1 = 45

Increase = 450 + 45 = €495

Since the decrease happens to the new number, the decrease and the decrease percentage both must be to the new changed number, which is 495

Decrease = 495 - (10%*495)

Again we must calculate the percentage of the decrease.

Decrease percentage = 10%*495 = 0.1*495 = 49.5

Decrease = 495 - 49.5 = 445.5

So, the value of Erika's ski chalet after the two changes = €445.5