Latest TCS Aptitude Question SOLUTION: Volume given 6*5*2 height constnt vol decreases by 19% so what is new breadth if l,b decrease in equal

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Volume given 6*5*2 height constnt vol decreases by 19% so what is new breadth if l,b decrease in equal

Asked In TCS Mohammad Asfar (10 years ago)

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j.s.b.subramanyam  (10 years ago)

So the volume of object=60....and its height is const.... after decreasing 19% it becomes...as l,b decrease by in equal ..assume that decrease be x... so new volume is (6-6x/100)*(5-5x/100)*2= (60-60*19/100)===>6*5*2(1-x/100)^2=48.6... on solving we get x=10.. so it is 10% decrease on l,b...and so l=5.4 and b=4.5.. hence new breadth is 4.5

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Vempa Siddhartha  (10 years ago)

since h is constant keep h aside. so V=lXb. given the volume is reduced by 19% so the new volume is (81/100)V. and given the decrease in l and b is same so the product of (9/10)l and (9/10)b contributes to (81/100)V. so the breadth is decreased by (1/10)b ie 10% of original b. so new b=4.5

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anjali dagar  (10 years ago)

v=l*b*h
take log
log v= logl+log b+ log h
partialy diffrntiate
dv/v= dl/l +db/ b
since h is constant therefore, its differentiation will be 0
where dv/v = -19 represent the percentage change in volume ,
dl/l =-x represent the % change in length ,
& db/b =-x represent the % change in breadth.
assume that decrease be x in both length & breadth
now, just put the values in above equation
-19=-x-x
x=19/2
=9.5(appx 10)
so length =6-(10*6/100)
=6-.6 i.e 5.4
lly, new breadth is 4.5

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vivek tripathi  (10 years ago)

let length & breadth decrease by x, -x-x+x^2/100=-19 by solving this you get x=10%. hence 5-10%5=4.5

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Guru Pranav  (10 years ago)

4.5 is the answer !!!

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