Circular Gears (GPREP)

[zagcollins]

Circular gears P and R start rotating at the same time at constant speeds. Gear P makes 10 revolutions per minute while gear R makes 4 revolutions per minute. How many seconds after the gears start rotating will gear R have made exactly 6 more revolutions than gear P?
A.6
B.8
C.10
D.12
E.15

OA is 12..need explanation for the same...

[sudhir3127]

Are you sure abt the Question? i feel something is wrong in it ...

[raunekk]

yup there is sumthg missing..

i thnk speed of R

[smclean23]

Since gear P makes 1 revolution every 6 seconds and gear R makes 2 revolutions every 3 seconds, you can set up an equation like so:


Rate of Gear P *X (seconds) + 6 = Rate of Gear R * X(seconds)

1/6 X + 6 = 2/3 X

Solve for x=12

[vishubn]

Since gear P makes 1 revolution every 6 seconds and gear R makes 2 revolutions every 3 seconds, you can set up an equation like so:

i agree with 1 rev every 6 seconds for p !!

but 2 rev every 3 sec

then according to this ! number of revolutions for R must be 40 not 4 ! if this a typo then i agree

if not somethings wrong with the question

Vishu

[vishubn]

yes My assumption was right
there is typo in the question ! its not 4 revolution on R's part instead it is 40 !!!

and the solution also holds good


find the link

https://www.beatthegmat.com/rt-d-question-t19104.html

Hth

Vishu