Average Problems( Week 23 Evaluation) 1. There are 6 math exams during the semester. Jackson has taken 5 exams so far and the scores were 86, 87, 88, 90, and 91. What will Jackson 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 9. The second group has 6 numbers with an average of 8 and the third group has 9 numbers with an average of 10. What is the average of all these numbers? 3. The average of 25 numbers is 16. One of numbers was then changed to 8. The average of all the numbers becomes 14 now. What was the number before it was changed? 4. There are 5 numbers. Their average is 12. The average of the first 2 numbers is 7. The average of the last 4 numbers is 18. What is the 2nd 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 10. What is the average of the first 11 numbers in the set? 6. The average of 7 numbers is 17. Let the 1st number increases by 2, the 2nd number by 4, the 3rd number by 6, the 4th number by 8 ... and the 7th number by 14. What is the average of all the increased numbers? 7. The average score of a math exam is 88 in a class. The average score of the 22 girls in the class is 89 for the exam. The average score of the boys in the class is 86 for the exam. How many boys are there in the class? 8. There are 2 groups of numbers. The first group has 6 numbers with an average of 4. The second group has 4 numbers with an average of 3. What new number can be added to the 2 groups of numbers to make all 11 numbers have an average of 5? 9. There are a total of 10 exams for the chemistry class in the semester. Hillary 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 18? |