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:
Explanation:
Let every question carry 1 mark. So total number of marks is 70.
Therefore passing marks = 60% of 70 = 42 marks.
Anita answered 70% of Arithmetic (10 Q) = 7
40% of Algebra (30 Q) = 12
60% of Geometry (30 Q) = 18
So, Anita's total marks = 7 + 12 +18 = 37 marks which is 5 short of 42.
So 5 more marks are required to pass the exam.