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Bill buys a stock that decreases by 20% on the first day, and then on the second day the stock increases by 30% of its value at the end of the first day. What was the overall percent increase in Bill's stock over the two days?

Aug 8, 2019

#1
+5798
+1

$$v_1 = (1-0.2)v_0 = 0.8v_0\\ v_2 = (1+0.3)v_1 = 1.3(0.8)v_0 =1.04v_0\\ \dfrac{v_2}{v_0} = 1.04 = (1+0.04)\\ \text{Overall there was a 4% increase in the stock value}$$

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Aug 8, 2019
#2
+103148
+1

Let P be the original price of the  stock

So we have, after  two  days

[ P (.80) ] (1.30)   =

P  * 1.04  ⇒      i.e., the  stock  has increased in value by 4%

Aug 8, 2019