Solve Sat Math: Find # Passengers on Bus Now

[hkhero]

At the first stop on its route, a bus picks up x passengers. At the second stop, y passengers get on the bus. At the third stop, 2/3 of the passengers exit the bus. At the fourth stop, 2 passengers get on the bus. How many passengers is the bus carrying right now?
a) (3x+3y+4)/3
b) (2x-2y-4)/3
c) (6-2x-2y)/3
d) (x+y+6)/3
e) (3x+2y+6)/3

I'm jux wondering hwo can u do this by using PLUG INS... thanks a lot... btw the answer is D.

 

[Hurkyl]

In my humble opinion, you should just figure it out directly, without resorting to some trick.

But if you're dead set on plugging things into solve the problem... then do it by plugging things in. If you're having problems, then show us what you've done, and where you're stuck!

 

[hkhero]

thatZ wt i did:
for ppl whoz orignally, i put 20 for that, then for x i put 3, and for y i put 4.
so first stop itz 20+3,
second stop itz 23+4,
third 27 * (1/3) = the ppl whoz left in the bus
fourth 9+2
so the total number is 11, but i couldn't find the answer... help! i think i have a problem about setting the original number of the bus.

 

[Hurkyl]

for ppl whoz orignally, i put 20 for that

Ah, that's your problem. The bus shouldn't have any passengers on board before it starts servicing its route!

 

[hkhero]

so it should be 0 for the orignally passenger?

 

[Office_Shredder]

Before the bus picks up x passengers, it should have zero on board. Otherwise, it kind of defeats the point of having a first stop.

I highly recommend you solve it by seeing how many passengers there must be in terms of x and y directly, otherwise you're going to be using a weak method that will only fail you later (or if it's not multiple choice)