# Increase and Decrease in Ratio

If the number of teachers in a college is increased from 50 to 60, then the ratio of new staff and old staff is:

We say that the number of teachers has been increased by the ratio 6 : 5. In other words, the number of new staff is times the number of old staff.

Hence

**Rule:**

To increase a no. “” we multiply by an improper fraction.

Similarly to decrease a no. “” we multiply by an proper fraction.

e.g. (1) Increase Rs. 20 by the ratio 6 : 5

New value =

e.g. (2) Decrease 56 by the ratio 7 : 8

New value =