Divide both fractions by the same number.
Given :
A hostel of 500 boys has provisions for 4 days.
To Find :
If the provisions were continued for 20 days, how many students have gone out of the hostel.
Solution :
Let, number of students left after 20 days are x.
Now, provisions are given by :

Also, provisions remains same.
So, initial provision = final provision

Therefore, 100 students have gone out of the hostel.
Hence, this is the required solution.
Answer:
The similar shortcut for division works because division is the opposite operation of multiplication—it “undoes” multiplication. If we move the decimal point to the right when multiplying by 10, 100, 1000 and so on, then it is quite natural that the rule for division would work the “opposite” way.
Step-by-step explanation: