Posted by **preston** on Thursday, October 2, 2008 at 4:33pm.

42 students took a test in school where the passing score was 70. the mean score of the 42 students taking the exam was 75.5 while the mean score of the students who passed the test was 81, and the mean score of the students who failed was 60. How many students passed the test?

- math -
**Reiny**, Thursday, October 2, 2008 at 4:42pm
Since the mean score of the 42 students was 75.5, the sum of all the scores of all students was 75.5(42)

let the number of students who passed be x

then 42-x must have failed

the sum of the scores of the passing students is then 81x, and

the sum of the scores of the failing students was (42-x)(60)

so isn't 81x + (42-x)(60) = (42)(75.5) ???

Take it from there

## Answer this Question

## Related Questions

- hard math - 42 students took a test in school where the passing score was 70. ...
- math algebra - 42 students took a test in school where the passing score was 70...
- math - 42 students took a test in school where the passing score was 70. the ...
- math - 42 students took a test in school where the passing score was 70. the ...
- Statistics - Students were given an exam with 300 multiple-choice questions. The...
- math - The mean score on a Math exam was 50% and the standard deviation was 10...
- Statistics - A group of 56 randomly selected students have a mean score of 30.8 ...
- Stats - A group of 56 randomly selected students have a mean score of 30.8 and a...
- statistics - Suppose that the mean score of an exam was 77 when taken 30 ...
- statistics - Suppose that the mean score of an exam was 77 when taken 30 ...

More Related Questions