Quiz Discussion

The average age of students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is-

• 1] 1 : 2
• 2] 2 : 3
• 3] 3 : 4
• 4] 3 : 5

The average age of P, Q and R is 15 years more than R's age. If the total age of P and Q together is 39 years, then R's age is ?

• 1] 12 years
• 2] 24 years
• 3] 16 years
• 4] 14 years

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

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

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

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

Find the average of all prime numbers between 30 and 50.

• 1]

  37.8

• 2]

  38.9

• 3]

  39.8

• 4]

  42.8

The average of six numbers is x and the average of three of these is y. If the average of the remaining three is z, then-

• 1] x = y + z
• 2] 2x = y + z
• 3] x = 2y + 2z
• 4] None of these

The average age of A, B, C, D and E is 40 years. The average age of A and B is 35 years and the average of C and D is 42 years. Age of E is :

• 1] 48 years
• 2] 46 years
• 3] 42 years
• 4] 45 years

A man travels equal distances of his journey at 40, 30 and 15 km/h. respectively. Find his average speed for whole journey.

• 1] 24
• 2] 25
• 3] 27
• 4] 28