2.2 Practical multiplication
The examples in Activity 4 helped you develop your understanding of multiplying fractions. You will now apply these new skills in a more practical situation in Activity 5.
Activity 5 Banking with fractions
In the New Policy Institute survey, it was found that of the 210 young people had bank accounts. Of these, had overdraft protection and approximately had debit cards.
- a.How many of the people surveyed had overdraft protection?
Hint: how many people from the group had a bank account? The word ‘of’ often translates into multiplication and a whole number can be written as a fraction by placing it over 1. What fraction of those with bank accounts have overdraft protection?
Answer
a. of 210 translates to
So, you know that 126 people have bank accounts. One third of this group have overdraft protection:
Therefore, 42 of the people surveyed have overdraft protection.
- b.How many survey participants had debit cards?
Hint: what fraction of the group with bank accounts also have debit cards?
Answer
b.You already know how many people have bank accounts: 126. You then need to find of this group.
You can calculate that people.
This fraction, it turns out, is an approximation. You need to interpret the results of your calculation carefully – particularly if it involves fractions of a person!
So, about 50 people have debit cards.
You might have approached the problem in Activity 5 differently to what was shown. Perhaps you found what one-fifth of the group was first by using division, and then used this portion to find three of those sets. Once you had this value, which indeed is 126 people, you could have then found the number of people with overdraft protection and debit cards as shown above. Both approaches are valid and will give you the correct answers. Choose whichever method is easier for you.
Now you’ve dealt with multiplication of fractions, you’ll move onto the last of the four basic operations of maths: division.