its one of these things i found on numerous IQ sites as well as in a few brain teasers. An example is given below. I would appreciate it if you could explain what the answer is and how you came to a conclusion. Cheers!
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Ten people can paint 60 houses in 120 days, so five people can paint 30 houses in:
2007-10-13 21:01:07 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Ten people can paint 60 houses in 120 days
One person can do 1/10 of that. 6 houses in 120 days
Meaning one person can paint 1 house in 20 days.
Five people can paint 5 houses in 20 days.
Five people can paint 30 houses (6 times as many) in 120 days. (6 times as long).
Or you could just see that you've got 50% of the manpower, and 50% of the workload, and realize that the time will be the same.
Of course, none of this is logical to actually assume and apply, because not all people work at the same pace, and conditions will vary. (Though more than enough people and companies don't seem to let that deter them.)
2007-10-13 21:06:29 · answer #1 · answered by Master Maverick 6 · 1⤊ 0⤋
10 people can paint 60 houses in 120 days. Then:
1 person can paint 60/(10*120) = 1/20 of a house in 1 day.
5 people can paint 5 * (1/20) = 1/4 of a house in 1 day.
30 = (1/4)t
t = 120 days <== answer
2007-10-14 04:20:24 · answer #2 · answered by 7 · 0⤊ 0⤋
1 people --60houses in 120*10 days
1 people --1 houses in 120*10/60days
5 people 1 house in 120*10/(60*5)
5 people 30 houses in 120*10*30/300 =120 days
2007-10-14 09:06:10 · answer #3 · answered by santmann2002 7 · 0⤊ 0⤋
Well you are cutting your staff in so its going to take them twice as long. So 5 people could paint 60 houses in 240 days or 30 in 120 days.
2007-10-14 04:13:41 · answer #4 · answered by Imbue 4 · 0⤊ 0⤋
To calculate how long 1 person take to do one house do this:
120 (days)/60(houses) *10(people) which is 20 days
So if it takes 20 days for 1 person to do one house then
30 houses / 5 people * 20 days (for one person to do one house) = 30/5 * 20 = 6 * 20 = 120
2007-10-14 04:12:13 · answer #5 · answered by ThE RiDdLeR 3 · 0⤊ 0⤋
120 days.
Half the people = twice as long.
Half the houses then knocks that time in half.
Therefore, same time as 10 people to paint 60 houses.
2007-10-14 04:05:21 · answer #6 · answered by Julian A 2 · 0⤊ 0⤋
Let x = no. of days.
Fastest way: ratio is 10 * 120:60 = 5x:30
60 * 5x = 10 * 120 * 30
300x = 36,000
x = 120
Answer: 120 days
Another way (formula):
(people * no. of days) * rate of person per day = no. of houses
Therefore:
(5 people * x) * ([60 houses /10 people]/120 days) = 30
5x * 0.05 = 30
0.25x = 30
x = 120
2007-10-14 04:46:38 · answer #7 · answered by Jun Agruda 7 · 2⤊ 0⤋
120 days
2007-10-14 04:31:29 · answer #8 · answered by fahad 2 · 0⤊ 0⤋
120 days again.
2007-10-14 04:03:59 · answer #9 · answered by timekiller unlimited 5 · 1⤊ 0⤋