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
- 2/3
- √2
- 5
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
الجبرا پر کون سی مسلمان سائنسدان نے پہلی کتاب لکھی ہے اور اسے الجبرا کے والد کے نام سے جانا جاتا ہے؟
- Ibn Sina
- Ibn Khaldun
- Al-Khwarizmi
- Euclid
اس سوال کو وضاحت کے ساتھ پڑھیں
