Hi All,
The 'key' to most 'rate' questions is to find a simple unit measure that's comparable for all the entities involved. In this prompt, we're dealing with 'total feet painted per volume of minutes.' Since the question asks for the number of MINUTES it takes to paint a fence, we should organize our information in terms of 'feet painted per minute.'
Based on the information in the prompt...
Ray paints 40 feet every 160 minutes = 1/4 foot per minute
Taylor paints 50 feet every 125 minutes = 2/5 foot per minute
In TOTAL, they paint 1/4 + 2/5 = 5/20 + 8/20 = 13/20 feet per minute
While that measurement might seem 'weird', we can convert it...
(13/20 feet per minute)(20 minutes) = 13 feet every 20 minutes
The prompt asks for the time it would take to paint a 260 foot long fence....
260/13 = (20 units of 13 feet) x 20 minutes = 400 minutes
Final Answer:
GMAT assassins aren't born, they're made,
Rich