Over a period of 2 years

The ratio 2012 is having wrong options...

agreed. for second part, the ratio of stock A to Stock B in 2012 = 0.8 * (100+a) / (100+b)

First of all the options are correct.
Now the most important point is the Easiest way to solve this question. Here it comes---

Lets assume price of stock A in 2010 = 80 (Pick any easy number)
Lets assume price of stock B in 2010 = 100 (Pick any easy number so that ratio of A/B is 0.8)
(We need to search for an option that will be equal to 100)

Because both A & B indicates percentage change in prices, lets assume A = B = 10% = 0.1(Pick any easy number)

So the price of Stock A in 2012 will be = 80 + 8 = 88
So the price of Stock B in 2012 will be = 100 + 10 = 110
So the ratio of Stock prices in 2012 will be = 88/110 = 8/10 = 0.8
(We need to search for an option that will be equal to 0.8)

Just put these values and you will get the answer.


Hope many will find it useful.

Fame

A12=A10 (1+A/100)

so the wrong answer for the second question.

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