Average Problems( Week 23 Evaluation) 1. There are 6 math exams during the semester. Eric has taken 5 exams so far and the scores were 83, 97, 87, 94, and 83. What will Eric need to score on his final math exam to have an average score of 88 for the semester? 2. There are 3 groups of numbers. The first group has 4 numbers with an average of 8. The second group has 5 numbers with an average of 9 and the third group has 11 numbers with an average of 13. What is the average of all these numbers? 3. The average of 38 numbers is 12. One of numbers was then changed to 10. The average of all the numbers becomes 9 now. What was the number before it was changed? 4. There are 5 numbers. Their average is 20. The average of the first 3 numbers is 18. The average of the last 3 numbers is 23. What is the 3rd 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 21 consecutive numbers is 18. What is the average of the first 15 numbers in the set? 6. The average of 9 numbers is 21. Let the 1st number increases by 2, the 2nd number by 4, the 3rd number by 6, the 4th number by 8 ... and the 9th number by 18. What is the average of all the increased numbers? 7. The average score of a math exam is 91 in a class. The average score of the 20 girls in the class is 92 for the exam. The average score of the boys in the class is 89 for the exam. How many boys are there in the class? 8. There are 2 groups of numbers. The first group has 5 numbers with an average of 5. The second group has 3 numbers with an average of 6. What new number can be added to the 2 groups of numbers to make all 9 numbers have an average of 7? 9. There are a total of 6 exams for the chemistry class in the semester. Emily got an average of 92 in the first 3 exams and 86 in the following 2 exams. What is the average she will need to score in the remaining exams in order to get an average of 90 for the semester? 10. What is the average of all three-digit numbers that are multiples of 15? |