01-02-2013, 05:18 PM
14-03-2013, 07:33 PM
(05-08-2012, 01:26 PM)Sritam Wrote: [ -> ]CBSE Class 10 Mathematics Question Paper 2011-2012 (SA-2)Hey anyone got the answer of the 34 th question ............ just need the final ans wer ony
Downlod it from the attachment
14-03-2013, 07:42 PM
Let C be the initial position of the plane above the ground and E the position of plane after 30 seconds.
Let the speed of the plane be ν m/sec.
Given ∠CAB = 60°, ∠EAD = 30°, BC = DE = 3600√3 m
Distance covered by the plane in 30 sec = ν m/sec × 30 sec = 30 ν m (Distance = Speed × Time)
∴ CE = BD = 30ν m
In ΔABC,
⇒ AB = 3600 m
In ΔADE,
⇒ 3600 + 30 ν = 3600 × 3
⇒ 30 ν = 10800 – 3600 = 7200
Speed of the plane = 240 m/sec = km/hr = 864 km/hr
Thus, the speed of the plane is 864 km/hr.