The average of five numbers is 20. If one number is excluded, the average becomes 18. What is the excluded number?
Practice Questions
1 question
Q1
The average of five numbers is 20. If one number is excluded, the average becomes 18. What is the excluded number?
22
20
18
16
Total of five numbers = 5 * 20 = 100. Total of four numbers = 4 * 18 = 72. Excluded number = 100 - 72 = 28.
Questions & Step-by-step Solutions
1 item
Q
Q: The average of five numbers is 20. If one number is excluded, the average becomes 18. What is the excluded number?
Solution: Total of five numbers = 5 * 20 = 100. Total of four numbers = 4 * 18 = 72. Excluded number = 100 - 72 = 28.
Steps: 3
Step 1: Calculate the total of the five numbers using the average. Since the average is 20 and there are 5 numbers, multiply 20 by 5. This gives you 100.
Step 2: Calculate the total of the four numbers after excluding one number. The new average is 18 and there are 4 numbers, so multiply 18 by 4. This gives you 72.
Step 3: Find the excluded number by subtracting the total of the four numbers from the total of the five numbers. So, subtract 72 from 100. This gives you 28.
