CBSE Class 10 Mathematics Question Paper 2011-2012 (SA-2)

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  • 2012
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    (05-08-2012, 01:26 PM)Sritam Wrote: CBSE Class 10 Mathematics Question Paper 2011-2012 (SA-2)


    Downlod it from the attachment
    Hey anyone got the answer of the 34 th question ............ just need the final ans wer ony

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    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.
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