The average of 15 numbers is 30, while the average of 13 of these numbers is 32. If the remaining two numbers are equal, then what is each of the two numbers?
- A17
- B31
- C16
- D34
Solution & Step-by-step Explanation
* Total sum of all 15 numbers:
Sum
15
=15×30=450
Total sum of 13 of these numbers:
Sum
13
=13×32=416
Sum of the remaining 2 numbers:
Sum
remaining 2
=Sum
15
−Sum
13
=450−416=34
Given that the remaining two numbers are equal, let each number be x:
2x=34⟹x=17
Sum
15
=15×30=450
Total sum of 13 of these numbers:
Sum
13
=13×32=416
Sum of the remaining 2 numbers:
Sum
remaining 2
=Sum
15
−Sum
13
=450−416=34
Given that the remaining two numbers are equal, let each number be x:
2x=34⟹x=17