Question for Important Examples: Averages
Try yourself:The average temperature on Wednesday, Thursday, and Friday was 25°. The average temperature on Thursday, Friday, and Saturday was 24°. If the temperature on Saturday was 27°, what was the temperature on Wednesday?
Explanation
The temperature on Wednesday was 30°.
Question for Important Examples: Averages
Try yourself:A class had 9 students. In one test, the class average was 61. One student's paper was scored incorrectly, and the resulting score was raised by 18 points. What is the corrected class average?
Explanation
The corrected average is 63.
Question for Important Examples: Averages
Try yourself:The average age of a group of 12 students is 20 years. If 4 more students join the group, the average age increases by 1 year. The average age of the new students is ____
Explanation
The average age of new students is 24 years.
Question for Important Examples: Averages
Try yourself:When a student weighing 45 kg left a class, the average weight of the remaining 59 students increased by 200 g. What is the average weight of the remaining 59 students?
Explanation
The average weight of the remaining 59 students is 57 kg.
Question for Important Examples: Averages
Try yourself:Three math classes: X, Y, and Z take an algebra test.
(i) The average score in class X is 83.
(ii) The average score in class Y is 76.
(iii) The average score in class Z is 85.
(iv) The average score of all students in classes X and Y together is 79.
(v) The average score of all students in classes Y and Z together is 81. What is the average score for all the three classes, taken together?
Explanation
The average score for all the three classes taken together is 81.5.
Question for Important Examples: Averages
Try yourself:The average weight of a class of 24 students is 36 kg. When the weight of the teacher is also included, the average weight increases by 1 kg. What is the weight of the teacher?
Explanation
The weight of the teacher is 61 kg.
Question for Important Examples: Averages
Try yourself:The average of 5 quantities is 10 and the average of 3 of them is 9. What is the average of the remaining 2?
Explanation
The average of the remaining 2 quantities is 11.5.
Question for Important Examples: Averages
Try yourself:The average age of a family of 5 members is 20 years. If the age of the youngest member is 10 years, what was the average age of the family just a day before the birth of the youngest member?
Explanation
The average age of the family, just a day before the birth of the youngest member, is 12.5 years.
Question for Important Examples: Averages
Try yourself:A student finds an average of 10 positive integers. Each integer contains two digits. By mistake, the student interchanges the digits of one number say ba for ab. Due to this, the average becomes 1.8 less than the previous one. What is the difference between the two digits a and b?
Explanation
The difference between the digits of the two-digit number is 2.
Question for Important Examples: Averages
Try yourself:Average cost of 5 apples and 4 mangoes is Rs. 36. The average cost of 7 apples and 8 mangoes is Rs. 48. What is the total cost of 24 apples and 24 mangoes?
Explanation
The cost of 24 apples and 24 mangoes is Rs. 2088.
Question for Important Examples: Averages
Try yourself:Average weight of 25 boys in a class is 48 kg. The average weight of a class of 40 students is 45 kg. What is the average weight of the 15 girls in the class?
Explanation
The average weight of the 15 girls is 40 kg.