A stock loses 10% of its value on Monday. On Tuesday it loses 20% of the value it had at the end of the day on Monday. On Wednesday it loses 30% of the value it had at the end of the day on Tuesday. What is the overall percent loss in value from the beginning of Monday to the end of Wednesday?
10 percent loss is 90% remaining
start at x value
at first day end = .9 x
at second day end = . 8 (.9x)
at third day end = .7 (.8)(.9x) = .504 x
so it lost 1 - .504 =.496 lost 49.6 %
What I like about this question is that you can set an amount for the stock price to easily solve it. Let's set the stock price to 100.
First day: lose 10%
Second day: lose 20%
Third day: lose 30%
In total, you lost 49.6$ over the whole period. As 49.6 is 49.6% of 100, you lost a total of 49.6%