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1) A rectangular field is to be fenced on three sides leaving a side of 40 feet uncovered. If the area of the field is 920 sq. feet, how many feet of fencing will be required?A) 86 B) 69 C) 90 D) 88
Answer & Explanation
Answer: 86 (We have: l = 40 ft and lb = 920 sq. ft.
So, b = 23.
Length of fencing = (l + 2b) = (40 + 46) ft = 86 ft.
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2) The length of a rectangle is halved, while its breadth is quadrapled. What is the percentage change in area?A) 80% B) 50% C) 100% D) 90
Answer & Explanation
Answer: 100% (Let original length = x and original breadth = y.
Original area = xy.
New length = x/2
New breadth = 4y.
New area = x/2 * 4y = 2xy.
Increase % = 1 xy x 1/xy x 100 % = 100%.
)
3) The difference between the length and breadth of a rectangle is 23 m. If its perimeter is 206 m, then its area is:A) 1986 B) 1966 C) 1985 D) 2520
Answer & Explanation
Answer: 2520 (We have: (l - b) = 23 and 2(l + b) = 206 or (l + b) = 103
Solving the two equations, we get: l = 63 and b = 40.
Area = (l x b) = (63 x 40) m2 = 2520 sq.m)
4) The diameter of a wheel is 14 cm.How many revolutions it will make in covering 44 km?A) 75000 B) 80000 C) 100000 D) 10000
Answer & Explanation
Answer: 100000 (Distance moved in one revolution = 2 * 22/7 * 7 = 44 cm.
Number of revolutions made in covering 44 km = 1000 * 44 * 100/44 = 100,000)
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