QUESTION

CSAT

Medium

Maths

Prelims 2016

Anita’s mathematics test had 70 problems carrying equal marks i.e., 10 arithmetic, 30 algebra and 30 geometry. 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% marks. The number of more questions she would have to answer correctly to earn a 60% passing marks is

Select an option to attempt

Explanation

Total number of problems = 70 The passing mark is 60% of 70, which is $0.60 \times 70 = 42$ marks.

Current performance:

Arithmetic problems: She answered 70% of 10 problems correctly, which is $0.70 \times 10 = 7$ correct answers.
Algebra problems: She answered 40% of 30 problems correctly, which is $0.40 \times 30 = 12$ correct answers.
Geometry problems: She answered 60% of 30 problems correctly, which is $0.60 \times 30 = 18$ correct answers.