Question

PLSSSS HELP

Brian's mathematics test had 85 problems: 20 arithmetic, 30 algebra, and 35 geometry problems. Although he answered 70% of the arithmetic problems, 40% of the algebra problems, and 60% of the geometry problems correctly, he didn't pass the test because he got less than 60% of the problems right. How many more questions would he have needed to answer correctly to earn a 60% passing grade?

Answer 1

4

Explanation:

You want to know how many more questions Brian needed to answer correctly to get a passing grade of 60% on his 85-question test, given that he answered correctly 70% of the 20 arithmetic problems, 40% of the 30 algebra problems, and 60% of the 35 geometry problems.

Correct answers

The number of correct answers Brian supplied was ...

0.70·20 +0.40·30 +0.60·35 = 14 +12 +21 = 47

The number of correct answers Brian needed for a passing grace was ...

0.60·85 = 51

Brian needed to answer 51 -47 = 4 more questions correctly to earn a passing grade.