Given:
a. The amount of flour that the bakery used this month was a 50% increase relative to last month.
So, we will draw a diagram that represents the situation
As shown, for last month, we have drawn a rectangle divided into two equal areas, each one represents 50%
this month was a 50% increase, so, we have drawn 3 areas which represent 50% increase
b. The amount of milk that the bakery used this month was a 75% decrease relative to last month.
As shown, for last month, we have drawn a rectangle with four equal areas
75% decrease, so, we have to remove 3 areas to make the remaining = 25%
So, the difference will give a 75% decrease