i hate maths

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Soldato
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If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together?

what sort of crap is this :mad:
 
My guess is 2.5 hours/2 hours 30 mins.

Average time to paint it = 5 hours.

5 hours split between the two = 2.5 hours.
 
Most obvious thing is it HAS to be less then 4 hrs. How on earth are ppl getting answers higher then that :confused:
 
Sally's painting speed = 1/4 houses per hour
John's painting speed = 1/6 houses per hour

Therefore together it is 1/4+1/6 = 5/12 houses per hour.

So, it's 12/5 hours to paint the house = 2.4 hours = 2 hours 24 minutes.
 
Haircut said:
Sally's painting speed = 1/4 houses per hour
John's painting speed = 1/6 houses per hour

Therefore together it is 1/4+1/6 = 5/12 houses per hour.

So, it's 12/5 hours to paint the house = 2.4 hours = 2 hours 24 minutes.

Exactly what I was about to say ;)
 
e36Adz said:
Most obvious thing is it HAS to be less then 4 hrs. How on earth are ppl getting answers higher then that :confused:



:o ooooops lol and i managed an a at gcse only 4 years ago so god help our country if exams are getting easier :(
 
Haircut said:
Sally's painting speed = 1/4 houses per hour
John's painting speed = 1/6 houses per hour

Therefore together it is 1/4+1/6 = 5/12 houses per hour.

So, it's 12/5 hours to paint the house = 2.4 hours = 2 hours 24 minutes.

i just worked that out too :p. Posted so it wasn't a complete waste :D.

1/4 per hour = 0.25
1/6 per hour = 0.1666666*

Combined is 5/12 (0.416666667 per hour)

5/12 * 2.4 = 1. So it takes them 2.4 hours.
 
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