Hi Vincen,
We're told that the number of rooms at Hotel G is 10 less than twice the number of rooms at Hotel H and that the total number of rooms at Hotel G and Hotel H is 425. We're asked for the number of rooms at Hotel G. This question can be solved by TESTing THE ANSWERS.
To start, we have a total of 425 rooms and we're told that Hotel G has 10 less than TWICE the rooms at Hotel H, so Hotel G clearly has a LOT more rooms than Hotel H does. Thus, we should start with one of the larger answers. Let's TEST Answer D.
IF.... Hotel G has 240 rooms
240 is 10 less than twice (H)
240 = 2H - 10
250 = 2H
125 = H
In this scenario, there would be 240+125 = 365 rooms. This is clearly TOO SMALL though (there are supposed to be 425 rooms), so we need both hotels to have more rooms. There's only one answer that allows for that.... If you want to prove the correct answer though, it would just take a bit more math...
IF.... Hotel G has 280 rooms
280 is 10 less than twice (H)
280 = 2H - 10
290 = 2H
145 = H
In this scenario, there would be 280+145 = 425 rooms. This is an exact match for what we were told, so this MUST be the answer.
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
