The question says that prices increase at a monthly rate of 1.5%.
We know that there are 12 months in a year.
To to find the percentage of yearly increase, we just need to multiply the monthly percentage by the number of months in a year.
1.5% = 0.015
0.015 * 12 = 0.18
0.18 = 18%
Therefore, the prices increase 18% in a year.
