Shobha’s mathematics test had 75 problems i.e.10 arithmetic, 30 algebra and 35 geometry problems. Although she answered 70% of the arithmetic ,40% of the algebra, and 60% of the geometry problems correctly. she did not pass the test because she got less than 60% of the problems right. How many more questions she would have to answer correctly to earn 60% of the passing grade?

A. 8

B. 6

C. 7

D. 5

Correct Answer :

D. 5

Number of questions attempted correctly=(70% of 10 + 40% of 30 + 60% 0f 35) =7 + 12+21= 45

questions to be answered correctly for 60% grade=60% of 75 = 45

therefore required number of questions= (45-40) = 5.