Homework Help: Maths

Posted by Annabella Richards on Monday, June 20, 2011 at 2:09am.

The teacher collected the test papers of 20 students and found that their average mark was 15. Before she wrote the marks in her mark book, she lost 1 paper. Find the mark for the missing paper, she worked out the average mark for the 19 students was 14. What was the mark on the missing paper?

Maths - PsyDAG, Monday, June 20, 2011 at 11:17am
Σx/n = mean

for 19 students Σx = 19 * 14 = 266

(266 + x)/20 = 15

Solve for x.

Answer this Question

Related Questions

maths - these marks were obtained by class of 28 students in a science test. the...
Probability and Statistics - For questions 1- 5 use confidence intervals to ...
math - The average score on a reading test for 58 students was 87.3. Twelve more...
Math - Period 1 has 15 students in it and a test average of 86%. Period 2 has 21...
PROBLEM SOLVING IN MATHEMATICS - the average age of a group of teachers and ...
Math - An instructor gives regular 20-point quizzes and 100-point exams in a ...
math - how do I do this? 28 students collected 12,374 soda can tabs. If some of ...
Algebra - Ms Newton's class took the same test as Mr. Euclid's students...
Algebra - Ms Newton's class took the same test as Mr. Euclid's students...
math - the average mark of 10 tests is 76%.If the average mark of the first 7 ...

For Further Reading

First Name:
School Subject:
Answer: