Quiz Discussion

Average of 80 numbers are 42. When 5 more numbers are included, the average of 85 numbers become 45. Find the average of 5 numbers.

• 1] 82
• 2] 89
• 3] 93
• 4] 98

If the average of x and 1/x(X\( \ne \)0) is M, then the average of x2 and 1/x² is :

• 1] 1 - M2
• 2] 1 - 2M2
• 3] 2M2 - 1
• 4] 2M2 + 1

Average of two numbers is 8 and average of other three numbers is 3; the average of the five numbers is :

• 1] 2
• 2] 3
• 3] 5
• 4] 6

A student finds the average of 10, 2 digits numbers. If the digits of one of the numbers interchanged, the average increases by 3.6. The difference between the digits of the 2 digits number is :

• 1] 4
• 2] 3
• 3] 2
• 4] 5

In 2011, the arithmetic mean of the annual incomes of Ramesh and Suresh was Rs. 3800. The arithmetic mean of the annual incomes of Suresh and Pratap was Rs. 4800, and the arithmetic mean of the annual incomes of Pratap and Ramesh was Rs. 5800. What is the arithmetic mean of the incomes of the three?

• 1] Rs. 4000
• 2] Rs. 4200
• 3] Rs. 4400
• 4] Rs. 4800

In a boat there are 8 men whose average weight is increased by 1 kg when 1 man of 60 kg is replaced by a new man. What is weight of new comer?

• 1] 70 kg
• 2] 66 kg
• 3] 68 kg
• 4] 69 kg

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

Out of 20 boys, 6 are each of 1 m 15 cm height, 8 are of 1 m 10 cm and rest of 1 m 12 cm. The average height of all of them is :

• 1] 1 m 12.1 cm
• 2] 1 m 21.1 cm
• 3] 1 m 21 cm
• 4] 1 m 12 cm

Amount five people with monthly income (in Rs.) 15000, 26000, 16000, 19000, 50000, how many will have income less than the mean income of five people?

• 1] 1
• 2] 2
• 3] 3
• 4] 4

Four years ago, the average age of a family of four persons was 18 years. During this period, a baby was born. Today if the average age of the family is still 18 years, the age of the baby is

• 1] 1.2 years
• 2] 2 years
• 3] 2.5 years
• 4] 3 years