A) Rs. 30 | B) Rs. 25 |

C) Rs. 20 | D) can't be determined |

Explanation:

Let the fixed expenditure of the hotel be Rs.x and the variable expenditure ( which is dependent on the guest ) is Rs.y , then

x + 10y = 600 ---------(1)

x + 20y = 800 ----------(2)

10y = 200

y = Rs. 20 and x= 400

Hence the total expenditure when there are 40 guests = 400 + 40 x 20 = 1200

average expenditure = = Rs. 30

A) 6 | B) 8 |

C) 4 | D) 5 |

Explanation:

Let the number of boys in the group originally be x.

Total weight of the boys = 30x

After the boy weighing 35 kg joins the group, total weight of boys = 30x + 35

So 30x + 35 + 31(x + 1) = > x = 4.

A) 33 yrs | B) 34 yrs |

C) 35 yrs | D) 36 yrs |

Explanation:

Total age of players in team = 22 x 11 = 242

When coach is included, total members = 12, Avg age increases by one becomes 23

Total age when coach is included = 23x12 = 276

Age of coach = 276-242 = 34 yrs.

A) 48 | B) 41 |

C) 45 | D) 43 |

Explanation:

3X + 4y = 240

by substitute through options 48 is correct

A) 22 | B) 21 |

C) 11 | D) 17 |

A) 84 km/hr | B) 96 km/hr |

C) 72 km/hr | D) 60 km/hr |

Explanation:

Let the speeds of the car, train and bus be 5x, 9x and 4x km/hr respectively.

Average speed = 5x + 9x + 4x/3 = 18x /3 = 6x km/hr.

Also, 6x = 72 => x = 12 km/hr

Therefore, the average speed of the car and train together is = = 7x = 7 x 12 = 84 km/hr.