In a town of 58800 houses, about 55 percent of the houses have pools. Determine the number of houses that have pools in this town.
Now, there’re different approaches that you might take to answer this question, depending on whether you have access to a calculator. We’ll consider one calculator and one non-calculator approach. Let’s consider the non-calculator approach first. We’re looking to calculate 55 percent of 58800. 55 percent could be split into 50 percent plus five percent. What I’m going to do is calculate 50 percent of 58800 and five percent of 58800 and add them together. To find 50 percent of a number, we need to divide by two. You could do this however you choose. But remember, we’re not using a calculator in this approach. So I’m going to use a bus stop division.
Two goes into five two times with a remainder of one. Two goes into 18 nine times with no remainder. Two goes into eight four times. And then for the remaining two zeroes, two doesn’t go in at all. So we have two zeros. Therefore, 58800 divided by two is equal to 29400. Next, I want to calculate five percent of 58800. And there are different ways of doing this. I could just divide 58800 by 20 for example. However, as I already know 50 percent and five percent is a tenth of that, then the simplest way is going to be to divide my calculation of 50 percent by 10. 29400 divided by 10 is 2940. In this case, we just lose one of the zeroes from the end of the number.
So now, I’ve worked out what 50 percent is and what five percent is. I just need to add them together to find 55 percent. I’ll do this using a column addition. So I’ll line up the two numbers that I’m adding from the right. Zero plus zero is equal to zero, and zero plus four is equal to four. So that’s added up the first two columns. Four plus nine is equal to 13. So I included three and then carry a one to the next column. Nine plus two plus one is equal to 12. So I write down the two and carry a one into the next column. Two plus one is equal to three, so we found that 55 percent of 58800 is 32340.
Now, there are other non-calculator approaches that you could’ve taken here. For example, you could divide 55 percent up into 10 percent five times and five percent and build it back up that way. Or you could perhaps find one percent by dividing 58800 by a 100 and then multiplying by 55. But I think the approach we’ve used here is the most straightforward. Now, let’s consider a calculator approach. When we see the word “of” in a percentage question, it means multiply. So in order to find 55 percent of 58800, we need to multiply.
Remember that percent means out of a 100. So 55 percent can be written as a fraction as 55 over 100. Now, we can perform this calculation. The 100 in the denominator does in fact cancel out two of the zeroes from 58800. So we’re left with 55 multiplied by 588. Remember, we’re assuming we do have access to a calculator for this approach. So we can evaluate 55 multiplied by 588 on our calculator. It’s 32340. So both approaches give the same result as we knew they should. The number of houses that have pools in the town is 32340.