Question
The angle of elevation of an aeroplane from a point on
the ground is 60°. After 12 seconds flight the elevation changes to 30°, if the aeroplane is flying at a height of 1440√3 m. find the speed of the aeroplane.Solution
Distance between two place in which angle change is D = n(cotθ₁ + cotθ₂) Distance = 1440√3 (cot30° + cot60°) = 1440√3 × √3 - 1/√3 = 1440√3 × 2/√3 = 2880 m So, distance covered by plane in 12 sec = 2880 m Speed of plane = 2880/12 = 240 m/sec.
Identify the logic of the below given series and given answer.
Series I :: 81, 89, 116, 241, (A), 1915
Series II :: (B), 204, 208, 4...
18 434 642 746 798 ?
...10, 22, 46, ?, 130, 190
12, 20, 36, ?, 132, 260
8 20 36 56 80 ?
If 152, 242, x , 332, 404, 314,
then find the value of (2x – 1)?
...21, 22, 48, 153, 628, ?
30 15 15 30 120 ?
...48 61 76 94 116 ?
If 4 2 x 1.5 0.5
Then, 1/3 x + 2.5 = ?
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