Area Problems The diameter of a circle is 105 cm less than the circumference. What is the diameter of the circle? 49 cm 44 cm 46 cm 48 cm 49 cm 44 cm 46 cm 48 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? ?d-d = 105 cm ? (? -1 ) d = 105 cm? [(22/7)-1] x d = 105 cm? d = (7/15) x 105 cm = 49 cm
Area Problems A rectangle has 20 cm as its length and 200 sq cm as its area. If the area is increased by 1 1/ 5 time the original area by increase its length only then the perimeter of the rectangle so formed (in cm) is 60 68 72 64 60 68 72 64 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP l1 = 20 cm, A1 = 200 sq cm? b1 = 200/20 = 10 cmNow, A2 = 200 x 6/5 = 240 sq cm b2 = 10 cm? l2 = 240/10 = 24 cm? Perimeter of new rectangle = 2(l2 + b2)= 2(24 + 10) = 2 x 34 = 68 cm
Area Problems An error 2% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is: 2.02% 4% 4.04% 2% 2.02% 4% 4.04% 2% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 100 cm is read as 102 cm. ∴ A1 = (100 x 100) cm2 and A2 (102 x 102) cm2. (A2 - A1) = [(102)2 - (100)2] = (102 + 100) x (102 - 100) = 404 cm2. ∴ Percentage error = ❨ 404 x 100 ❩% = 4.04%
Area Problems Find the area of a rectangle having 15m length and 8m breadth. 125 sq m 111 sq m 120 sq m 115 sq m 125 sq m 111 sq m 120 sq m 115 sq m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Required area = Length x Breadth= 15 x 8 = 120 sq m
Area Problems The length of hall is (4/3) times its breadth. If the area of hall be 300 square meters, the difference between the length and the breadth is? 4 meters 15 meters None of these 3 meters 4 meters 15 meters None of these 3 meters ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let breadth = b meters.Then, length = 4b/3 meters.? b x 4b/3 = 300? b2 = 300 x 3/4 ? b2 = 225? b = 15Hence, required difference = [(Length) - (Breadth) ]= 4b/3 - b = b/3= 15/3 m= 5 m
Area Problems The radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is? 36.25 km/hr. 31.68 km/hr. 32.72 km/hr. 29.46 km/hr. 36.25 km/hr. 31.68 km/hr. 32.72 km/hr. 29.46 km/hr. ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Circumference = 2?r = 2 x (22 / 7) x 70 cm = 440 cm Distance travelled in 10 revolutions = 440 x 10 cm = 4400 cm = 44 m? Speed = distance / time= 44 / 5 m/sec= (44 / 5) x (18 / 5) km/hr = 31.68 km/hr
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