I am stuck on this question style my teacher gives me each week. I have no idea to answer it and it hurts my brain! Please would you give some time to help me and walk me through this question:
- 8 cleaners can clean an office block in 3 hours. If the block needs to be cleaned in 2.5 hours, how many cleaners will be needed?
I've tried things like:
8 * 3 = 24
24/2.5 = 9.6
8 / 3 = 2.66666667
2.66666667 * 2.5 = 6.66666668
[8/3 = N/2.5
8*N = 3*2.5] I think I'm wrong here so I gave up this bit...
and...
went here:
8/3 = N/2.5
8*2.5 = 3*N
20 = 3N
N = 20 / 3
I don't know where I'm at any more! Would any of you guys help me?
Much appreciated,
t.madx
Obviously it takes $3 * 8 = 24$ hours to clean the office. Ideally the work can be parallelized without loss, which I assume.
To clean the office in 2.5 hours time you'll need $24 / 2.5 = 9.6$ cleaners. It will be hard to find a "0.6" cleaner. Hence you'll need 10.
In a real life situation this probably won't work.
Just think of washing the dishes. If 2 people can wash the dishes in 1 hour time, is it reasonable to assume that 10 people can do the same in 12 minutes? There will be such a crowd in front of the sink that it's likely they'll need even more than an hour.