Let length = L and breadth = BLet , New breadth = ZThen, New length = ( 160 / 100) L.= 8L / 5? 8L / 5 x Z = LBor Z = 5B/8Decrease in breadth = (B-5B/8)= 3B/8? Decrease in percent = (3B/8 x1/B ) x 100 %= 371/2%
Area of the plot = (3 x 1200) m2= 3600 m2Let breadth = y metersThen Length = 4y meters,Now area = 4y x y = 3600 m2? y2 = 900 m2? y = 30 m? Length of plot = 4y m= (4 x 30) m=120 m
Let the radius of circular field = r m.Speed of person in m/s = 30/60 = 1/2m/sAccording to the question,[(2?r) /(1/2)] - [(2r)/(1/2)] = 30? 4?r - 4r = 30? [4 x (22/7) - 4]r =30? (125 - 4)r = 30 ? (8.5)r = 30? r = 30/8.5 = 3.5 m
Diameter of the circle = 13 + 5 = 18 cm? Radius = Diameter/2 =18/2 = 9 cm Area of the circle = ?r2 = (22/7) x 92 = (22 x 81)/9 = 1782/7 = 254.57 sq cm= 255 sq cm
clearly the cow will graze a circular field of area 9856 sq m and radius equal to the length of the rope.
Let the length of the rope be r mts then,
= 9856
= (9856 × 7) / 22 = 3136
r = 56 m
speed = 12 km/h = 12 × 5 18 = 10 3 m / s distance covered = 20 × 2 × 22 7 × 50 = 44000 7 m time taken = distance /speed = 44000 7 × 3 10 s e c = 4400 × 3 7 × 1 60 m i n = 220 7 m i n
EXAMIANS