Latest Elitmus Aptitude Question SOLUTION: a basketball is dropped from a height of 20 feet.it bounces back each time to a height which is one half of the height of the last bounce.how far approximatesly will the ball have

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(#M40013719) ELITMUS Numerical Ability question Keep an EYE

a basketball is dropped from a height of 20 feet.it bounces back each time to a height which is one half of the height of the last bounce.how far approximatesly will the ball have to be travelled before it comes to rest?

A)30FT.
b)40
C)60
d)CANNOT B DETERMINED

Asked In Elitmus Saurabh Sachdeva (12 years ago)

Solved Vinay Sipani Read Solution (9)

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Read Solution (9) :

Vinay Sipani   (12 years ago)

1st time = 20 ft
2nd time = 10ft down + 10 ft up
3rd time = 5ft up + 5ft down
and so on

Total distance travelled = 20 + (10 + 10) + (5 + 5) + (2.5 + 2.5) + . . .
= 20 + (10 + 5 + 2.5 + ...) + (10 + 5 + 2.5 + ...)
Assuming the ball comes to rest at infinity,

Total distance travelled = 20 + [ 10/ (1 - 0.5) ] + [ 10/ ( 1 - 0.5) ]
= 20 + 20 + 20 = 60

Is this solution Helpfull? Yes (79) | No (6)  

Amit kumar  (12 years ago)

using formula of impact,
when any object is dropped from a height of h1 .it bounces back each time to a height which is h2.the total distance covered by object(it comes to rest)
H= h1*(1+k)/(1-k), where k= squrt(h2/h1)

h1=20, h2=10 ==> total distance H= 3*20= 60 feet.

Is this solution Helpfull? Yes (20) | No (2)  

shakti prakash mishra  (11 years ago)

20 + 2(10+5+2.5+....)
apply formula of infinite G.P
a/(a+r),where r=1/2
20+2(10/1-1/2)= 60 feet

Is this solution Helpfull? Yes (15) | No (3)  

AVINASH KUMAR  (11 years ago)

TOTAL DISTANCE THAT BALL HAVE TO TRAVEL IS
20+10+10+5+5+2.5+2.5+1.25+1.25+.625+.625+.......
20+20+10+5+2.5+1.25+..........
20+(20/(1-1/2))
20+40
i.e
60

Is this solution Helpfull? Yes (8) | No (1)  

RAHUL RAUTH  (11 years ago)

here is a trick if ball drop for 3/4 or 1/2 or smthng like ths... then(1+2)*height.
so we get, according to d question,
(1+2)*20=60 (100 % sure)

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vinod  (11 years ago)

it is in the form of gp in which we can use the formulae s=a/1-r+((1/2a)/1-r))
where a=20 s=1/2

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chander  (10 years ago)

lets assume its a series of nth gp...so first calculate in one direction...
downwards 20(1-12)=40
upwards a=10 half height
10(1-12)=20
so total travelled=60

Is this solution Helpfull? Yes (1) | No   

vikaskumar jaisal  (9 years ago)

cannot b determined becouse we dont know what is the lower level of the bounce ball

Is this solution Helpfull? Yes (1) | No (5)  

Suryam  (8 years ago)

40(b)
20/3/2=13
20+13+14=40

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