Quiz Discussion

Out of four numbers the average of the first three is 16 and that of the last three is 15. If the last number is 20, than first number is :

• 1] 25
• 2] 21
• 3] 23
• 4] 28

The average score of a cricketer for ten matches is 38.9 runs. If the average for the first six matches is 42, then find the average for the last four matches.

• 1] 33.25
• 2] 33.5
• 3] 34.25
• 4] 35

The average of first five multiples of 3 is:

• 1] 9
• 2] 10
• 3] 8
• 4] 11

The average weight of 3 men, A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E whose weight is 3 kg more than that of D, replaces A then the average weight of B, C, D and E becomes 79 kg. What is the weight of A ?

• 1] 70 kg
• 2] 72 kg
• 3] 75 kg
• 4] 80 kg

Of the three numbers, the first is twice the second and the second is twice the third. The average of the reciprocal of the numbers is 7/72. The numbers are:

• 1] 36, 18, 9
• 2] 24, 12, 6
• 3] 20, 10, 5
• 4] 16, 8, 4

A train covers the first 16 km at a speed of 20 km per hour another 20 km at 40 km per hour and the last 10 km at 15 km per hour. Find the average speed for the entire journey.

• 1]

  24 km

• 2]

  26 km

• 3]

  21 km

• 4]

  km

The average of x number is y and average of y numbers is x. Then the average of all the numbers taken together is

• 1]

  (x+y)/2xy

• 2]

  2xy/(x+y)

• 3]

  (x²+y²)/(x+y)

• 4]

  xy/(x+y)

If the arithmetic mean of 7, 5, 13, x and 9 is 10, then the value of x is :

• 1] 10
• 2] 12
• 3] 14
• 4] 16

The average marks obtained by a class of 60 students is 65. The average marks of half of the students is found to be 85. The average marks of the remaining students is :

• 1] 35
• 2] 45
• 3] 55
• 4] 65

The average of the ages of Sumit, Krishna and Rishabh is 43 and the average of the ages of Sumit, Rishabh and Rohit is 49. If Rohit is 54 years old, what is Krishna’s age?

• 1] 24 years
• 2] 36 years
• 3] 45 years
• 4] Cannot be determined
• 5] None of these