x% of a quantity is taken or added by the first, y% of the remaining is taken or added by the second and z% of a quantity is taken or added by the first, Now if A is the amount left then find the initial amount :
initial amount =
initial amount =
| Ax100x100x100 |
| (100+x)(100+y)(100+z) |
After reducing 10% from a certain sum and then 20% from the remaining , there is Rs 3600 left then find the original sum.
Solution:
original sum =
| 3600x100x100x100 |
| (100-10)(100-20) |
Example 2:
A man had Rs 4800 in his locker. Two years ago in the first year he deposited 20% of the amount in his locker. In second year he deposit 25% of increased amount find the left over amount in the locker.
Solution:
left amount : 4800 =
| Ax100x100x100 |
| (100+20)(100+25) |
In a library 20% of the books are in hindi , 50% of the remaining are in English 30% of the remaining are in french, the remaining 6300 books are in regional language, total no of books would be?
Solution:
Total no of books =
| 6300x100x100x100 |
| (100-20)(100-50)(100-30) |