Sandy gets 3 marks for each correct sum and loses 2 marks for each incorrect sum. Sandy attempts 30 sums and obtains 65 marks. How many sums did Sandy get correct?	Choose the correct answer:
A) 19
B) 21
C) 23
D) 25
E) 27
Let x be the correct sums and (30-x) be the incorrect sums.   3x - 2(30-x) = 65   5x = 125   x = 25   The answer is 25.
<result>D</result>
Sandy gets 3 marks for each correct sum and loses 2 marks for each incorrect sum. Sandy attempts 30 sums and obtains 65 marks. How many sums did Sandy get correct?