In an election between two candidates A and B, the number of valid votes received by A exceeds those received by B by 15% of the total number of votes polled. If 20% of the votes polled were invalid and a total of 8720 votes were polled, then how many valid votes did B get?
Choose the correct option:
A) 1888  B) 2999  C) 2834  D) 2777  E) 2991
Let the total number of votes polled in the election be 100k.   Number of valid votes = 100k - 20% (100k) = 80k   Let the number of votes polled in favour of A and B be a and b respectively.   a - b = 15% (100k) =&gt; a = b + 15k   =&gt; a + b = b + 15k + b   Now, 2b + 15k = 80k and hence b = 32.5k   It is given that 100k = 8720   32.5k = 32.5k/100k * 8720 = 2834   The number of valid votes polled in favour of B is 2834.   Answer: 283432.5 /100  * 8720= 
<gadget id="calculator">32.5 /100  * 8720</gadget>
<output>2_834</output>
2834   The number of valid votes polled in favour of B is 2834.   Answer: 2834
<result>C</result>
In an election between two candidates A and B, the number of valid votes received by A exceeds those received by B by 15% of the total number of votes polled. If 20% of the votes polled were invalid and a total of 8720 votes were polled, then how many valid votes did B get?