This is from the 5lb book and the correct answer is B. I thought it was A because the question did not specify that the price increase in May was being compared to the beginning of April. I assumed it was compared to the end of April so I am just analyzing a month of price increase for both quantities A and B. Am I wrong to assume that?
Price in March = 100
Price in April = 100 * 1.4 = 140
Price in May = 140 * 1.3 = 182
Price increase in April = 140 - 100 = 40
Price increase in May = 182 - 140 = 42
The question never mentions anything about comparison, it just asks how much price increases in each month. I will suggest just keep it simple.