1. The ratio of the length and the breadth of a rectangle is 4 : 3 and the area of the rectangle is 6912 sq cm. Find the ratio of the breadth and the area of the rectangle?
A. 1 : 96
B. 1 : 48
C. 1 : 84
D. 1 : 68
E. None of these
Answer: Option A
Explanation:
Let the length and the breadth of the rectangle be 4x cm and 3x respectively.
(4x) (3x) = 6912
12[latex]{x}^{2}[/latex] = 6912
[latex]{x}^{2}[/latex] = 576 = 4 × 144 = 22 × 122 (x > 0)
=> x = 2 × 12 = 24
Ratio of the breadth and the areas = 3x : 12[latex]{x}^{2}[/latex] = 1 : 4x = 1: 96.
2. The area of the square formed on the diagonal of a rectangle as its side is 108 1/3 % more than the area of the rectangle. If the perimeter of the rectangle is 28 units, find the difference between the sides of the rectangle?
A. 8
B. 12
C. 6
D. 2
E. None of these
Answer: Option D
Explanation:
Let the sides of the rectangle be l and b respectively.
From the given data,
(√[latex]{l}^{2} + {b}^{2}[/latex]) = (1 + 108 [latex]\frac{1}{3}[/latex] %)lb
=> [latex]{l}^{2} + {b}^{2}[/latex] = (1 + [latex]\frac{325}{3}[/latex] × [latex]\frac{1}{100}[/latex])lb
= (1 + [latex]\frac{13}{12}[/latex])lb
= [latex]\frac{25}{12}[/latex] lb
=> [latex]{l}^{2}[/latex] + [latex]\frac{{b}^{2}}{lb}[/latex] = [latex]\frac{25}{12}[/latex]
12[latex]{l}^{2} + {b}^{2}[/latex] = 25lb
Adding 24lb on both sides
12[latex]{l}^{2}[/latex] + 12[latex]{b}^{2}[/latex] + 24lb = 49lb
12([latex]{l}^{2} + {b}^{2}[/latex] + 2lb) = 49lb
but 2(l + b) = 28 => l + b = 14
12[latex]{(l + b)}^{2}[/latex] = 49lb
=> 12[latex]{(14)}^{2}[/latex] = 49lb
=> lb = 48
Since l + b = 14, l = 8 and b = 6
l - b = 8 - 6 = 2m.
3. The length of a rectangular plot is thrice its breadth. If the area of the rectangular plot is 867 sq m, then what is the breadth of the rectangular plot?
A. 8.5 m
B. 17 m
C. 34 m
D. 51 m
E. None of these
Answer: Option B
Explanation:
Let the breadth of the plot be b m.
Length of the plot = 3 b m
(3b)(b) = 867
3[latex]{b}^{2}[/latex] = 867
[latex]{b}^{2}[/latex] = 289 = 172 (b > 0)
b = 17 m.
4. The length of a rectangular floor is more than its breadth by 200%. If Rs. 324 is required to paint the floor at the rate of Rs. 3 per sq m, then what would be the length of the floor?
A. 27 m
B. 24 m
C. 18 m
D. 21 m
E. None of these
Answer: Option C
Explanation:
Let the length and the breadth of the floor be l m and b m respectively.
l = b + 200% of b = l + 2b = 3b
Area of the floor = [latex]\frac{324}{3}[/latex] = 108 sq m
l b = 108 i.e., l × [latex]\frac{1}{3}[/latex] = 108
l2 = 324 => l = 18.
5. An order was placed for the supply of a carpet whose breadth was 6 m and length was 1.44 times the breadth. What be the cost of a carpet whose length and breadth are 40% more and 25% more respectively than the first carpet. Given that the ratio of carpet is Rs. 45 per sq m?
A. Rs. 3642.40
B. Rs. 3868.80
C. Rs. 4216.20
D. Rs. 4082.40
E. None of these
Answer: Option D
Explanation:
Length of the first carpet = (1.44) (6) = 8.64 cm
Area of the second carpet = 8.64 (1 + [latex]\frac{40}{100}[/latex]) × 6 (1 + [latex]\frac{25}{100}[/latex])
= 51.84 (1.4) ([latex]\frac{5}{4}[/latex]) sq m = (12.96) (7) sq m
Cost of the second carpet = (45) (12.96 × 7) = 315 (13 - 0.04) = 4095 - 12.6 = Rs. 4082.40