A school has 8 periods a day each of 45 minutes duration. How long would each period be, if the school has 9 periods a day, assuming the number of school hours to be the same?
Let the duration of each period, when there are 9 periods a day in the school, be x minutes. The following table is obtained.
Duration of each period (in minutes) |
45 |
x |
Number of periods |
8 |
9 |
If there is more number of periods a day in the school, then the duration of each period will be lesser. Hence, this is a case of inverse proportion. Therefore
45 × 8 = x× 9
Hence, in this case, the duration of each period will be 40 minutes.