An masons build a wall in 10days.how many days will it take for 5 masons to build the same wall?
Answers
Answer:
This type of question makes a few assumptions. It assumes that tasks can be broken up into evenly divisible sub-tasks so that the more workers you have, the faster the task can be completed. This is sort of an approximation. Take this assumption to its extremes to say why it isn't going to hold in extreme cases. For example, in reality having 24 times as many workers isn't necessarily going to mean the wall can be completed in 20 hours
The wall takes 20*15 mason days to build. To find the number of mason days you have, take the number of masons you have and multiply by the number of days available for building.
That's really wordy. To make our math more compact, let's agree to represent the number of masons by a letter. How about M for mason?
Let's agree to represent the time available in days with a letter as well. How about D for days?
We are saying that a measure of the amount of effort it takes to build this wall (let's call this E for effort) is to take the number of masons working and multiply by the number of days they would need to work to finish the wall.
E = M * D
We are told that 15 masons can build the wall in 20 days. This tells us something about how big of a wall we are talking about.
E = M * D
= 15 masons * 20 days = 300 mason days
In the new situation, we are asked about building the same wall (so E is still 300 mason days), but with fewer days available. The new value of D will be 12 days.
In our new equation,
we have
E = M * D
300 mason days = x masons * 12 days
Solve for x. What can you do to both sides of the equation?
We can treat the units as if they were actual values. We can divide both sides by mason(s) and divide both sides by day(s).
I put (s) because it doesn't matter whether we use mason or masons. The fact we change the word (typically by adding an s suffix) when there is more than one of something is just a quirk of the English language. In math, the singular or plural versions of a unit can be ignored.
That leaves us with just the numerical equation
300 = x * 12.
Step-by-step explanation: