Maths Questions (1 Viewer)

[cutemouse]

It takes John about 5 hours to paint a house. It takes Bob about 3 hours to paint the same house. About how long will it take to paint the house if both of them work together?

 

[clintmyster]

It will be just under 2 hrs i.e. 112 minutes and 30 seconds

basically i broke it up in hours so john achieves 1/5 of the work per hour and bob acheives 1/3. Combined effort = 8/15. So 8/15 x what = 15/15 where 15/15 is the complete building of the house. This is basically 15/8 and multiply by 60 to get the figure i did.

 

[fullonoob]

ahaha this question was in maths comp

 

[Meepo]

It will be just under 2 hrs i.e. 112 minutes and 30 seconds

basically i broke it up in hours so john achieves 1/5 of the work per hour and bob acheives 1/3. Combined effort = 8/15. So 8/15 x what = 15/15 where 15/15 is the complete building of the house. This is basically 15/8 and multiply by 60 to get the figure i did.

Your correct =)

It is 1/5 + 1/3 = 8/15

1 divided 8/15 = 15/8
= 1.875

Then you use that figure and press that degree minute button on your calculator.

Which gives you 1hr 52mins 30 seconds.

 

[biopia]

I think the conversion from 112.5 to hours and minutes was implied in clintmyster's answer :/ I wouldn't say it's "incorrect".

15/8 * 60 = 112.5 = 1 hour 52 minutes and 30 seconds.