Question
A racetrack is in the form of a ring whose inner
circumference is 220 m, and the outer circumference is 352 m. Find the area of the track [Use π = 22/7]Solution
ATQ, Given: Inner circumference of racetrack (in the ring form) = 220m Outer circumference of racetrack =352m Let the radius of inner track be 'r' 2πr=220m[ Circumference of the circle =2πr] 2 × 22/7 × r = 220m r = (220m × 7)/(2 × 22) = 35m Let the radius of inner track be 'R' 2πr = 352m [ Circumference of the circle =2πr] 2 × (22/7) × R = 220m R = (352m × 7)/(2 × 22) = 56m ∴Width of track = radius of outer track − radius of inner trac = 56 - 35 = 21m Area of the track = Area of outer track − Area of the inner track πR2 -πr2 [∵ Area of the circle = π(radius)2} π(R2 - r2) π(R− r)(R+r)[∵(a2−b2)=(a−b)(a+b)] = (22/7) × (56m - 35m)(56m+35m) = (22/7) × 21m × 91m = (42042/7) = 6006 m²
24, 42, 60, ?, 96, 114
What will come in place of (?) question mark in the given number series.
10, 17, 26, 37, 50, ?
660, 653, 639, 618, 590, ?
What will come in place of the question mark (?) in the following series?
75, 219, 388, ?, 809, 1065168, 178, ?, 273, 400, 618, 963
60   61    57   66    ?      75    39
...What will come in place of the question mark (?) in the following series?
2, 5, 14, 41, 122, 365, ?
81, 83, 87, 95, 111, ?
What will come in place of the question mark (?) in the following series?
400, 841, 1202, ?, 1716, 1885
64, 66, 69, 74, 81, ?