412 x 0.05 = 20.6 = 20 members
20 members x 9 months = 180 members
412 members + 180 members = 592 members
If it wasn’t people then the equation would be
412 x 0.05 = 20.6
20.6 x 9 = 185.4
412 + 185.4 = 597.4
Some people may confuse the first part as you can’t have .6 of a person, but they might just multiply it by 9 to equal 185 people, but if it multiplies by 5% each month then there’s 20 people joining each month. That’s what the question is asking. With each 5% joining each month, how many will there be after 9 months.
The answer is 592 members.