A) 55% | B) 65% |

C) 75% | D) 85% |

Explanation:

Let original radius = R.

New radius = =

Original area = and new area =

Decrease in area = = 75%

A) 90% | B) 88% |

C) 85% | D) 84% |

Explanation:

Let length, breadth and height of the room be 7, 3, 1 unit respectively.

Area of walls = 2(l+b)xh = 2(7+3)x1 = 20 sq. unit.

Now, length, breadth and height of room will become 3.5, 6 and 2 respectively.

Area of walls = 2(l+b)xh = 2(3.5+6)x2 = 38 sq. unit.

% Increase in the area of walls = (38-20)x100/20 = 90%.

A) 18 cm | B) 12 cm |

C) 16 cm | D) 14 cm |

Explanation:

circumference of a circle = 2r

=> 2 × 22/7 × r – r = 37

=> 37/7 × r = 37

=> r = 7 cm.

Diameter D = 2r = 7×2 = 14 cm.

A) 65700 sq.m | B) 54500 sq.m |

C) 78700 sq.m | D) 67500 sq.m |

Explanation:

Let the length be 'l' and breadth be 'b'.

b = l × 3/4__________(a)

2(l+b) = 1050

l+b = 525___________(b)

From equations (a) and (b),

l = 300m, b = 225 m

Area = l × b

= 300 × 225

= 67500 sq.m.

A) 12.50 cm | B) 14.21 cm |

C) 15.98 cm | D) 17.08 cm |

Explanation:

Let the length of the rectangle = L cm

Then the breadth of the rectangle = (L - 10) cm

Perimeter of a rectangle = 2(L + B) cm

=> 44 = 2(L + L - 10)

=> 44 = 4L - 20

=> 4L = 64

=> L = 16 cm

=> B = L - 10 = 6 cm

Diagonal = = = 17.08 cm

A) Rs. 4680 | B) Rs. 7600 |

C) Rs. 6000 | D) Rs. 5480 |

Explanation:

Total are of all stairs = 50 (20x60 + 30x60)

= 50 (1200 + 1800)

= 50 x 3000

= 150000 sq cm.

Given rate of 100 sq cm = Rs. 4

Then for 150000 sq. cm = ?

=> 4 x 150000/100 = Rs. 6000