Elitmus
Exam
Numerical Ability
Number System
A basket ball is dropped from hight at 24 feet it bounce back each time to a height which is one half of the height of the last bounce.how for approxmately will the ball have traveled before it comes ?
a) 12 b) 24 c) 72 d)can't be deteremined
Read Solution (Total 15)
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- ANS: c)72
24+(12+12)+(6+6)+(3+3)+.......
= 24+2*[12+6+3.....]
= 24+2*[12/(1-1/2)] (INFINITE GP a/(1-r))
= 24+48
= 72 - 10 years agoHelpfull: Yes(53) No(0)
- as it has been dropped from 24 feet so the ball will travell approximately
= 24 + (12+12)+ (6+6)+(3+3) + (1.5+1.5)+ (.75+.75)....
= 72 - 10 years agoHelpfull: Yes(4) No(1)
- when the ball is dropped it first travel 24 feet in downwards direction then it bounces back again upto 24 feet then then after every bounce its height reduces by 1/2 i.e
24+[24+12+6+3+2+1+....]
its in g.p and has infinite terms so
s= 24/(1-1/2)
s=48
total=48+24
i.e 72 option c - 10 years agoHelpfull: Yes(4) No(0)
- here the height is decreased by half ..so consider r = 1/2..
first term is 24 and scond term will be 12..
so the formula for this type of Geometric progression is
(first term/(1-r))+(second term/(1-r))
i.e 24/(1/2) + 12(1/2) = 48+24 = 72..ans c)72 - 10 years agoHelpfull: Yes(2) No(0)
- ANSWER==>72
1st bounce to 24 feet
2nd bounce to 12 feet
it will continue till comes to rest. So its a infinite GP.
24/(1-1/2)+12/(1-1/2)=72 feet - 10 years agoHelpfull: Yes(2) No(0)
- it will be =24+2*24( 1/2 + (1/2)^2 upto infinity)
24+48* (1/2)/1-(1/2)=72 - 10 years agoHelpfull: Yes(1) No(0)
- 24+12+12+6+6+3+3+1.5+1.5+0.75+0.75+0.3+0.3~=72
- 10 years agoHelpfull: Yes(1) No(0)
- This forms the infinite gp so 24*2 + 12*2 =72
- 10 years agoHelpfull: Yes(1) No(0)
- Total Disatance Travveled by the ball = 24+(12+12)+(6+6)+(3+3)+............
so, 24+2*(12+6+3+........)
24+2*[12/(1-1/2)]
24+48
72 Ans - 10 years agoHelpfull: Yes(1) No(0)
- 24 12 12 6 6 3 3...
24+(24+12+6+....)
24+(24/(1-.5))=24+48=72 - 10 years agoHelpfull: Yes(0) No(0)
- 72 Each time the ball bouces to half the height , so form a geometric progression with first term 24 and common ratio 1/2 upto infinity . the sum of an infite G.P is the answer .
- 10 years agoHelpfull: Yes(0) No(0)
- it will be a geometric progression. and the distance =24+2*(24/2+24/4+24/8+24/16 +24/32+.......)
distance D=24*(1+2*(1/2+1/4+1/8+1/16+........)
D=24*(1+2*(0.5/(1-0.5))=24*(1+2)=72 answer. - 9 years agoHelpfull: Yes(0) No(0)
- can't be determined :)
- 9 years agoHelpfull: Yes(0) No(8)
- 72 approx becoz 24+(24/2)*2+(12/2)*2+(6/2)*2+(3/2)*2+(1.5/2)*2+(.75/2)*2=71.625
we multiply by 2 becoz it bounce and cm back by covering same distance and divide by 2 becoz it always bounce half of previous distance - 8 years agoHelpfull: Yes(0) No(0)
- #Trick given 24feet and bounce back 1/2
so 24*(1+2)/ (2-1)=72 - 7 years agoHelpfull: Yes(0) No(0)
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