Question

If 12 pencils cost $4.00, how much does 20 pencils cost?

Answer 1

Answer:

$\huge\boxed{\ 6\dfrac{2}{3}\approx\ 6.67}$

Step-by-step explanation:

$\bold{METHOD\ 1:}\\\\\begin{array}{ccc}12&-&\ 4.00\\\\20&-&\ x\end{array}\qquad\text{cross multiply}\\\\12x=(20)(4)\\\\12x=80\qquad\text{divide both sides by 12}\\\\x=\dfrac{80}{12}\\\\x=\dfrac{20}{3}\\\\x=6\dfrac{2}{3}\Rightarrow x\approx6.67$

$\bold{METHOD\ 2:}\\\\12\ \text{pencils cost}\ \ 4.00.\\\\1\ \text{pencil cost}\ \ 4.00:12=\ \dfrac{4}{12}=\ \dfrac{1}{3}\\\\20\ \text{pencils cost}\ \ \dfrac{1}{3}\times20=\ \dfrac{20}{3}=\ 6\dfrac{2}{3}\approx\ 6.67$

Answer 2

Answer:

$6.66

Step-by-step explanation:

20 times 4 = 80 and 80 divided by 12 is 6.66666667