A body falls 16m in the first second of its motion 48m in the next second 80m in the 3rd second and ...........

Quantitative Aptitude ( CCS) Time & distance

A body falls 16m in the first second of its motion,48m in the next second,80m in the 3rd second and so on.How long will it take to fall 4096m?

16 sec

20 sec

24 sec

30 sec

16,48,80............... which is AP

let it takes N seconds to fall 4096m

therfor sum of series for N terms=4096

or (N/2)(2*16+(N-1)*32)=4096

or, 16(N^2)=4096

or, (N^2)=4096/16=256

or N=16

Hence, option 1 is the correct answer.

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