# Average Questions

**FACTS AND FORMULAE FOR AVERAGE QUESTIONS**

**1**. Average =$\frac{Sumofobservations}{No.ofobservations}$

**2**. Suppose a man covers a certain distance **x** kmph and an equal distance at** y** kmph. Then, the average speed during the whole journey is$\frac{2xy}{x+y}$Kmph

A) 25 | B) 23 |

C) 19 | D) 18 |

Explanation:

Sum of the present ages of husband, wife and child = (23 * 2 + 5 * 2) + 1 = 57 years.

Required average = (57/3) = 19 years.

A) 12 | B) 13 |

C) 14 | D) 15 |

Explanation:

i) Let the ages of the five members at present be a, b, c, d & e years.

And the age of the new member be f years.

ii) So the new average of five members' age = (a + b + c + d + f)/5 ------- (1)

iii) Their corresponding ages 3 years ago = (a-3), (b-3), (c-3), (d-3) & (e-3) years

So their average age 3 years ago = (a + b + c + d + e - 15)/5 = x ----- (2)

==> a + b + c + d + e = 5x + 15

==> a + b + c + d = 5x + 15 - e ------ (3)

iv) Substituting this value of a + b + c + d = 5x + 15 - e in (1) above,

The new average is: (5x + 15 - e + f)/5

Equating this to the average age of x years, 3 yrs, ago as in (2) above,

(5x + 15 - e + f)/5 = x

==> (5x + 15 - e + f) = 5x

Solving e - f = 15 years.

Thus the difference of ages between replaced and new member = 15 years.

A) 17 | B) 29 |

C) 36 | D) 48 |

Explanation:

Let the first number be x,

Then, sum of the four numbers = x + 4x = 5x.

so, 5x/4 = 60 or x = (60 * 4) / 5 = 48.

A) 34 | B) 36 |

C) 35 | D) 37 |

A) m:25.50 w:27.50 | B) m:27.50 w:22.50 |

C) m:26.50 w:27.50 | D) m: 24.50 w:26.50 |

Explanation:

Let the daily wage of a man be Rs. x.

Then, daily wage of a woman = Rs. (x - 5).

Now, 600x + 400 (x - 5) = 25.50 * (600 + 400) <=> 1000x = 27500 <=> x = 27.50.

Man's daily wages = Rs. 27.50; Woman's daily wages = (x - 5) = Rs. 22.50.

A) 20 | B) 21 |

C) 23 | D) 24 |

Explanation:

Lot the total number of workers be v Then,

8OOOv = (12000 * 7) + 6000 (v - 7) <=> 2000v = 42000 <=> v = 21.

A) 665 | B) 657 |

C) 658 | D) 678 |

Explanation:

Let the total score be x.

(x + 92 - 85) / 8 = 84.

So, x + 7 = 672 => x = 665.

A) 35 years | B) 45 years |

C) 51 years | D) 54 years |

Explanation:

Age of the teacher = (37 * 15 - 36 * 14) years = 51 years.