Going into a recent election, only about 62% of people old enough to vote were registered. in a community of about 55,200 eligible voters, how many people were registered?

All we need to do is to divide the number of eligible voters by 62% to find out how many people have been registered:

55200 ÷ 62% =
= 55200 ÷ 62/100 =
= 55200 * 100/62 =
= 5520000 / 62 =
= 89032,25806451613 ≈          (note the rounding to the nearest whole number)
≈ 89032

Doublecheck:

89032 * 62% =
= 89032 * 62/100 =
= 5519984 / 100 =
= 55199,84 ≈                        (the difference is because of the rounding before)
≈ 55200

There were 89,032 people registered.