Quiz Discussion

What is the average of the first six (positive) odd number each of which is divisible by 7?

• 1] 42
• 2] 43
• 3] 47
• 4] 49

The average height of 30 boys out of a class of 50 is 160 cm. If the average height of the remaining boys is 165 cm, the average height of the whole class (in cm) is :

• 1] 161
• 2] 162
• 3] 163
• 4] 164

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

A cricketer whose bowling average is 12.4 runs per wicket takes 5 wickets for 26 runs and thereby decreased his average by 0.4. The number of wickets taken by him the last match was-

• 1] 64
• 2] 72
• 3] 80
• 4] 85

Find the average of first 97 natural numbers.

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

A passenger travels from Delhi to Merut at a speed of 30 kmph and return with a speed of 60 kmph. What is the average speed?

• 1] 40
• 2] 45
• 3] 50
• 4] 48

30 pens and 75 pencils altogether were purchased for Rs. 510. If the average price of a pencil was Rs. 2, what was the average price of a pen ?

• 1] Rs. 9
• 2] Rs. 10
• 3] Rs. 11
• 4] Rs. 12

a, b, c, d, e, f, g are consecutive even numbers. j, k, l, m, n are consecutive odd numbers. The average of all the numbers is :

• 1]

  \(3\left( {\frac{{a + n}}{2}} \right)\)

• 2]

  \(\left( {\frac{{1 + d}}{2}} \right)\)

• 3]

  \(\left( {\frac{{a + b + m + n}}{4}} \right)\)

• 4]

  \(3\left( {\frac{{j + c + n +g}}{4}} \right)\)

The average age of 40 students of class is 18 years. When 20 new students are admitted to the same class, the average age of the students of the class is increased by 6 months. The average age of newly admitted students is ?

• 1] 19 years
• 2] 19 years 6 months
• 3] 20 years
• 4] 20 years 6 months

If the mean of 4 observations is 20, when a constant 'c' is added to each observation, the mean becomes 22. The value of c is :

• 1]

  6

• 2]

  -2

• 3]

  2

• 4]

  4