Question

Jenny knit a total of 12 centimeters of scarf over 2 nights. How many nights will Jenny have
to spend knitting in order to knit a total of 18 centimeters of scarf? Assume the relationship is
directly proportional.

Answer 1

As we can assume the relationship is directly proportional, we have to build the proportion and do the cross product. So:

$\begin{gathered} \frac{12cm}{\text{2 nights}}=\frac{18cm}{x\text{ nights}} \\ 12x=2\cdot18 \\ 12x=36 \\ x=\frac{36}{12} \\ x=3 \end{gathered}$

She needs 3 nights