Jack enters a lift on the 5th floor, which is going up @ 17 floors/min speed. At the same time Jill

M4maths Previous Puzzles

09 Nov 2018 Lift

Jack enters a lift on the 5th floor, which is going up @ 17 floors/min speed. At the same time Jill

enters another lift on the 180th floor which is going down @ 18 floors/min speed. At what floor will

they be together?

OPtion

1) 80
2) 90
3) 100
4) 75
5) 85
6) 95
7) 81
8) 91
9) 101
10) None of these

Solution

Relative Speed = 17+18 = 35 floors/min
Relative Distance = 180 - 5 = 175 floors

Time to cover 170 floors with relative speed = 175*60/35 = 300 seconds

Floors travelled by Jack in 300 seconds = (17/60)*300 = 85
Floors on which they will meet = 5 + 85 = 90th
Option 2)

Correct Option: 2 Best Solution (12)

Devendra Marghade   5 years AGO

Their relative speed=17+18=35 floors/min.
So they will meet after (180-5)/35 min=175/35=5 min.
In 5 min. Jill will come down 18*5=90 floors from 180 floors.
Hence they will be together at 180-90=90th floor.
Option 2)

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SAYAN CHATTERJEE   5 years AGO

5+17x= 180-18x
x= 5.
Hence the floor no is 5+17*5= 90.
Option 2.

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Shanjay Sundar . D   5 years AGO

Let X be the place two meet
using the speed distance formula
X-5/17=180-X/18
by solving 18X-90=3060-17X
35X=3150
X=90
so my option is 2

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Shyam Sundar . D   5 years AGO

let X be the place two meet , using the speed distance formulae
X-5/17=180-X/18
by solving
18X-90=3060-17X
35X=3150
X=90
so my option is 2

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Madhu Gopal Thota   5 years AGO

Let x be time of travel
5

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V manikandan   5 years AGO

Let to floor be 180 and bottom flour be 5
consider Jill travel for five min ..then he travel 5*18=90 flours 180-90=90th floor
consider jack travel for five min.. then he travel 5*17=85 floors ..as he started at 5th flour..then add five floors
85+5=90
thus they will meet at 90th floor

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Kariamal   5 years AGO

Jack 17 floor/min up and jill 18 floor/min down, so 90 floor they will meet together

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Priya   5 years AGO

They will meet at 90 because 1st will travel at the speed of 17floor/min at 5min (17*5=85+5floor remaining ) and 2nd will travel at the speed of 18 floor/min ie (18*5=90). So at 90 floor they will meet

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Manas   5 years AGO

It forms an AP
Jack: 5,22,39,....
Jill: 180,162,144,...
The first common number is 90 i.e. 90th floor

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ARINJOY GHOSH   5 years AGO

Let, they will meet after k min. from time of entering in lift.
so,
180-18k=5+17k
k=175/35=5
at that time they are in floor no.=5*17+5=90
Ans. option (2)

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Ayapu sirisha   5 years AGO

for one minute lift goes up 17 floors
for the same one minute lift goes down 18 floors
for the 5 minutes lift goes up at 80 th floor
for the same 5 minuts lift goes down at 80 th floor

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keerthana datla   5 years AGO

22,39,56,73.... for first lift ap
162,144,126 ... for second lift in ap
solving we get 90

Like? Yes | No (1)