Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Question 2: The share price of a public company fell 4% on each day of a week, from Monday to Friday. What is the price of a share at the end of the trading day on Friday, if the share was valued at $20 on the Sunday of the same week?

I could do this the long way by calculating the depreciation for each day as: monday: 20 -4% of 20 tuesday:monday-4% of monday wed: tuesday-4% of tuesday and so on to friday

This method takes a lot of time. What is the shortest way of finding the answer? could depreciation formula could be used for it?

share|cite|improve this question
rate falls only from monday to friday – pradip Aug 22 '12 at 2:48
Weekends - No rise, no fall, just steady? – Frenzy Li Aug 22 '12 at 2:49
I thought weeks started on Mondays! – Frenzy Li Aug 22 '12 at 2:59
ans is (1 - .04)^5·$20 – pradip Aug 22 '12 at 3:00
up vote 4 down vote accepted

The closing price on Friday is $20(0.96)^5$.

Similarly, if the price increases by say $6\%$ each day, then in $5$ days it gets multiplied by $(1.06)^5$.

share|cite|improve this answer

Sunday - price = $20$

Monday - $20 \times 0.96$

Tuesday - $20 \times 0.96^2$

Wednesday - $20 \times 0.96^3$

Thursday - $20 \times 0.96^4$

Friday - no weekend days to consider - price = $20 \times (0.96)^5$

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.