Question

Rebecca had 9/10 of a yard of ribbon. Then she gave 7/20 of a yard to a friend. How much does she have left? Explain your work

Answer 1

Answer: $\dfrac{11}{20}$ yards

Step-by-step explanation:

By considering the given information , we have

The total initial length of ribbon = $\dfrac{9}{10}$ yards

The length of ribbon she gave to her friend = $\dfrac{7}{20}$ yards

The length of ribbon she has left = Initial length - Length she gave

$=\dfrac{9}{10}-\dfrac{7}{20}$

$=\dfrac{9\times2}{10\times2}-\dfrac{7}{20}$ [Multiply 2 on numerator and denominator to the first fraction to make both fractions like.]

$=\dfrac{18}{20}-\dfrac{7}{20}$

$=\dfrac{18-7}{20}=\dfrac{11}{20}$

hence, the length of ribbon she has left = $\dfrac{11}{20}$ yards

Answer 2

rewrite fraction s to have common denominator:

9/10 = 18/20

 now subtract:

18/20 - 7/20 = 11/20 left