Average Problems( Week 23 Evaluation) 1. There are 6 math exams during the semester. David has taken 5 exams so far and the scores were 91, 87, 82, 83, and 98. What will David need to score on his final math exam to have an average score of 87 for the semester? 2. There are 3 groups of numbers. The first group has 5 numbers with an average of 4. The second group has 4 numbers with an average of 5 and the third group has 11 numbers with an average of 16. What is the average of all these numbers? 3. The average of 14 numbers is 16. One of numbers was then changed to 7. The average of all the numbers becomes 15 now. What was the number before it was changed? 4. There are 9 numbers. Their average is 20. The average of the first 6 numbers is 21. The average of the last 4 numbers is 20. What is the 6th number? 5. Consecutive numbers are natural numbers that follow in order, such as 1,2, 3, 4, 5,..., and so forth. Suppose the average of 13 consecutive numbers is 16. What is the average of the first 7 numbers in the set? 6. The average of 11 numbers is 19. Let the 1st number increases by 1, the 2nd number by 2, the 3rd number by 3, the 4th number by 4 ... and the 11th number by 11. What is the average of all the increased numbers? 7. The average score of a math exam is 92 in a class. The average score of the 22 girls in the class is 93 for the exam. The average score of the boys in the class is 90 for the exam. How many boys are there in the class? 8. There are 2 groups of numbers. The first group has 4 numbers with an average of 9. The second group has 6 numbers with an average of 8. What new number can be added to the 2 groups of numbers to make all 11 numbers have an average of 10? 9. There are a total of 8 exams for the chemistry class in the semester. Alice got an average of 78 in the first 3 exams and 84 in the following 3 exams. What is the average she will need to score in the remaining exams in order to get an average of 80 for the semester? 10. What is the average of all three-digit numbers that are multiples of 14? |