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) 15 cm | B) 18 cm |

C) 34 cm | D) 26 cm |

Explanation:

Let the side of the square be 's' cm

length of rectangle = (s+5) cm

breadth of rectangle = (s-3)cm

(s+5) (s-3) =

- 5s - 3s - 15 =

2s = 15

Perimeter of rectangle = 2(L+B) = 2(s+5 + s–3) = 2(2s + 2)

= 2(15 + 2) = 34 cm

A) 187 cm | B) 178 cm |

C) 149 cm | D) 194 cm |

Explanation:

Area of square = 40 x 40

= 1600 sq.cm

Given that the areas of Square and Rectangle are equal

=> Area of rectangle = 1600 Sq.cm

We know that, Area of rectangle = L x B

Given L = 64 cm

Breadth of rectangle = 1600/64 = 25 cm

Perimeter of the rectangle = 2(L + B) = 2(64+25) = 178 cm.

A) Only statement A is required | B) Only statement B is required |

C) Both A & B are required | D) Neither (A) nor (B) is reuired |

Explanation:

From statement (A),

20b = (1/2) × b × h

h = 40 cm.

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.