Question

Albert has $\frac{5}{7}$ m of ribbon. He used $\frac{3}{5}$ m of ribbon to make bows for his friends. How much ribbon did Albert left with?

• A. $\frac{3}{35}$
• B. $\frac{4}{35}$
• C. $\frac{46}{35}$
• D. $\frac{13}{35}$

Answer 1

The correct option is B $\frac{4}{35}$

Amount of ribbon Albert left with = Amount of ribbon Albert start with - Amount of ribbon used by him
$=\frac{5}{7}-\frac{3}{5}$

As these are unlike fractions, we need to convert them into like fractions.

Step 1: Find the LCM of denominators 7 and 5

Multiples of 7: 7, 14, 21, 28, 35, 42, ...
Multiples of 5: 5, 10, 15, 20, 25, 30, 35, 40, ...

35 is the common multiple of 7 and 5. So, LCM of 7 and 5 is 35.

$\frac{5}{7}=\frac{5\times 5}{7\times 5}=\frac{25}{35}$
$\frac{3}{5}=\frac{3\times 7}{5\times 7}=\frac{21}{35}$

$\therefore \frac{5}{7}-\frac{3}{5}=\frac{25}{35}-\frac{21}{35}$
$=\frac{25-21}{35}$
$=\frac{4}{35}$
Albert left with $\frac{4}{35}$ m of ribbon.