the population this year is 15 I think because 60 = 100% so if you divide 60 into two you will get 30 / 50%. then divide 30 again which would be 15 and that's 25 percent. only if you know what 60 divides by 2 and then 30 divided by 2.
There are 3 nickels because if you use the ratio 6 to 1 you multiply 6 by 3 to get 18 pennies and you do the same with the one and that’s how I got 3 nickels.