Problem solving help
- Thread starter vokster
- Start date
In problems like this it makes it easier (for me at least) to keep track of units. Since time to complete a task is ofter measured in man-days [or probably person-days now], that is the type of unit I'll use.
To show you the method, we'll try the old problem of "If a chicken and half can lay an egg and a half in a day and a half, how long would it take 1 chicken to lay one egg". If one and a half chickens all work one and a half days that is 1.5*1.5 = 2.25 chicken-days. So 2.25 chicken-days for one and half eggs is 2.25/1.5 = 1.5 chicken-days for one egg. If we have one chicken working then it will take 1.5 chicken-days/(1 chicken) = 1.5 days to lay one egg. So the answer is "It will take 1 chicken 1.5 days to lay one egg".
For your problem, it takes 4*10 = 40 painter-days to paint a house.
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- Feb 4, 2004
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The general method for solving this sort of exercise involves algebra. Some lessons on the topic, showing how to set up and solve these problems, can be found here.
One arithmetical (rather than algebraic) method would be to think in terms of man-hours (or, in this case, man-days). If two guys each work for three hours, that's six man-hours. In your case, four guys work for ten days. How many man-days is this?
Given this total number of man-days necessary to complete the entire task, if you divide these man-days between FIVE guys, how many days will they need?
