Quiz Discussion

There are 30 students in a class. The average age of first 10 students is 12.5 years. The average age of the remaining 20 students is 13.1 years. The average age (in years) of the students of the whole class is :

• 1] 12.5 years
• 2] 12.7 years
• 3] 12.8 years
• 4] 12.9 years

The average age of a family with 5 members is 28. If one of the 5 members of age 20 is excluded the average age of the family becomes -

• 1] 25
• 2] 20
• 3] 30
• 4] 24

Find the average of first 97 natural numbers.

• 1] 47
• 2] 37
• 3] 48
• 4] 49
• 5] 49.5

Sachin Tendulkar has a certain average for 11 innings. In the 12th innings he scores 120 runs and thereby increases his average by 5 runs. His new average is :

• 1] 60
• 2] 62
• 3] 65
• 4] 66

If 25a + 25b = 115, what is the average of a and b?

• 1] 2.5
• 2] 3.4
• 3] 4.5
• 4] 4.6
• 5] None of these

The average monthly income of P and Q is Rs. 5050. The average monthly income of Q and R is Rs. 6250 and the average monthly income of P and R is Rs. 5200. The monthly income of P is-

• 1] Rs. 3500
• 2] Rs. 4000
• 3] Rs. 4050
• 4] Rs. 5000

Mean of 10 numbers is 30. Later on it was observed that numbers 15, 23 are wrongly taken as 51, 32. The correct mean is :

• 1] 25.5
• 2] 32
• 3] 30
• 4] 34.5

A man started his journey from Lucknow to Kolkata, which is 200 km, at the speed of 40 kmph then he went to Banglore which is 300 km, at the speed of 20 kmph. Further he went to Ahmedabad which is 500 km, at the speed of 10 kmph. The average speed of the man is :

• 1]

  kmph

• 2]

  Kmph

• 3]

  15.6 kmph

• 4]

  16.1 kmph

The average (arithmetic mean) of 330, 360 and 390 is :

• 1]

  \({3^{27}} + {3^{57}} + {3^{87}}\)

• 2]

  \({3^{29}} + {3^{59}} + {3^{89}}\)

• 3]

  \({3^{60}}\)

• 4]

  \({3^{177}}\)

The average of four consecutive even numbers is 15. The 2nd highest number is :

• 1] 12
• 2] 18
• 3] 14
• 4] 16