This can be solved algebraically. Before we start, as context, to find a percentage you multiply by the percentage/100.
This tells us that 90 is 120% of 75. However, your question wants us to find the <em>increase</em>, therefore we don't need that 100.
Therefore, the increase is 20%.
This tells us that 90 is 120% of 75. However, your question wants us to find the <em>increase</em>, therefore we don't need that 100.
Therefore, the increase is 20%.