
By: Phoenix (offline) Thursday, August 09 2012 @ 12:14 AM CDT (Read 1112 times)



Phoenix 
A bus left the interchange with some passengers on board. At bus stop A, 10 passengers boarded the bus. When it reached Bus Stop B, 3/4 of the passengers alighted. The bus continued its journey and at Bus Stop C, 2/3 of the passengers alighted while 3 passengers boarded the bus. There were 18 passengers on the bus when it left Bus Stop C. How many passengers were on the bus when it left the interchange?

Newbie
Registered: 12/31/11 Posts: 14





By: jo sarah (offline) Thursday, August 09 2012 @ 08:58 AM CDT



jo sarah 
Hi,
We start from the end  call it "Working Backward":
Left Stop C: 18 ... these include the 3 who boarded.
so, without those boarding, there were 18  3 = 15, which is 1/3 of no. when it arrived at C
so, when arrived at C, it had 15 x 3 = 45 (same as when left
Left Stop B: 45 ... 3/4 alighted i.e what left is 1/4;
so, no. when arrived at B = 45 x 4 = 180 (same as when left A)
Left Stop A: 180 ... included 10 who boarded
so, actually had 180  10 = 170 when arrived at A
which is the no. it left the Interchange with.
So, the bus left Interchange with 170 passengers.
Check:

Interchange: 170
At A: 170 + 10 = 180
At B: 135 alighted, left with 45
At C: 30 alighted, 3 boarded, so 18
Cheerio!

Regular Member
Registered: 03/20/12 Posts: 111





By: jo sarah (offline) Thursday, August 09 2012 @ 09:01 AM CDT



jo sarah 
Sorry, i didn't draw that smiley face... the system corrupted my typing...
words there was to mean:
..... same as when left Stop B

Regular Member
Registered: 03/20/12 Posts: 111





By: Phoenix (offline) Thursday, August 09 2012 @ 10:04 PM CDT



Phoenix 
Thank Sarah, appreciate your help.

Newbie
Registered: 12/31/11 Posts: 14



