Jayant gets 3 marks for each right sum and loses 2 marks for each wrong sum. He attempts 30 sums and obtains 40 marks. The number of sums attempted correctly is	Choose the correct choice from the following choices:
A) 25
B) 20
C) 26
D) 27
E) 28
this is linear eqn in 2 variable   the Ist eqn   3x - 2y = 40   x + y = 30   solving   x = 20 (right answer)   y = 10 (wrong answer)   ANSWER:20
<result>B</result>
Jayant gets 3 marks for each right sum and loses 2 marks for each wrong sum. He attempts 30 sums and obtains 40 marks. The number of sums attempted correctly is