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) 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.

A) 22 | B) 36 |

C) 32 | D) 26 |

Explanation:

Total number of students = 54 x 30

When arranged in rows of 45, number of rows formed are,

= 36.

A) Rs. 1495 | B) Rs. 548 |

C) Rs. 850 | D) Rs. 1750 |

Explanation:

Let the average bill paid by twenty members = 'x'

But 19 men paid each = Rs. 70

20th man paid Rs. 90.25 more than the avg bill of 20 = x + 90.25

20x = 19(70) + x + 90.25

19x = 1330 + 90.25

19x = 1420.25

x = 1420.25/19 = Rs. 74.75

But the total bill = 20 x 74.75 = Rs. 1495.