Quiz Discussion

The average marks of four subjects is 120. If 33 was misread as 13 during the calculation, what will be the correct average?

• 1] 122
• 2] 120
• 3] 125
• 4] 121

The average of 50 numbers is 30. If two numbers, 35 and 40 are discarded, then the average of the remaining numbers is nearly:

• 1] 28.32
• 2] 29.68
• 3] 28.78
• 4] 29.27

The average weight of a group of 75 girls was calculated as 47 kgs. It was later discovered that the weight of one of the girls was read as 45 kgs. Whereas her actual weight was 25 kgs. What is the actual average weight of the group of 75 girls? ( Rounded off to two digits after decimal).

• 1] 34
• 2] 36
• 3] 30
• 4] None of these

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 mean weight of 100 students in a class is 46 kg. The mean weight of boys is 50 and of girls is 40 kg. Therefore, the number of boys is:

• 1] 50
• 2] 60
• 3] 70
• 4] 65

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

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

The average score of a class of boys and girls in an examination is A. The ratio of boys and girls in the class is 3 : 1. If the average score of the boys is A + 1, the average score of the girls is-

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

The average age of three boys is 15 years. If their ages are in ratio 3 : 5 : 7, the age of the youngest boy is

• 1] 21 years
• 2] 18 years
• 3] 15 years
• 4] 9 years
• 5] 12 years

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