The average of 6 numbers is 30. If the average of the first four is 25 and that of the last three is 35, the fourth number is?
- 15
- 30
- 25
- 20
Explanation
- Avg of 6 numbers = 30
- Sum of 6 numbers = 6 x 30 = 180
- Avg of first 4 numbers = 25
- Sum of first 4 numbers = 4 x 25 = 100
- Avg of last 3 numbers = 35
- Sum of last 3 numbers = 3 x 35 = 105
- Now, let's find the 4th number:
- Sum of first 3 numbers = Sum of first 4 numbers - 4th number
- = 100 - 4th number
- Sum of first 3 numbers = Sum of all 6 numbers - Sum of last 3 numbers
- = 180 - 105
- = 75
- So, 75 = 100 - 4th number
- 4th number = 100 - 75
- = 25
Related MCQs
- Always irrational
- Always an integer
- Always rational
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
- Cubic root
- Index
- Radical
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
- 72 km/h
- 60 km/h
- 80 km/h
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
