Problems on average of average ages

Problems on average of average ages

#### If a class of 30 students has an average age of 15 years, what is the total age of the class? 1. [x] 450 2. [ ] 500 3. [ ] 550 4. [ ] 600 #### The average of three numbers is 20. If the average of the first two numbers is 15, what is the third number? 1. [ ] 20 2. [ ] 25 3. [x] 30 4. [ ] 35 #### A bag has 5 balls with an average weight of 20 grams. What is the total weight of the balls? 1. [ ] 80 2. [x] 100 3. [ ] 120 4. [ ] 140 #### Six friends have an average age of 24 years. What is the total of their ages? 1. [ ] 120 2. [x] 144 3. [ ] 168 4. [ ] 216 #### The average of ten numbers is 10. If the average of the first 8 numbers is 7, what is the the sum of remaining numbers? 1. [ ] 20 2. [ ] 25 3. [x] 44 4. [ ] 35