A cook

A cook wants to make enough cookies for 159 students. The cookie recipe makes 1 1/4 dozen cookies. A dozen equals 12. How many batches does the cook need to make if each student gets one cookie?

Correct answer:

n =  11

Step-by-step explanation:

$$\begin{gathered} d=1\frac{1}{4}\cdot 12=\frac{5}{4}\cdot 12=\frac{5\cdot 12}{4}=\frac{60}{4}=15 \\ {n}_1=159/d=159/15=\frac{53}{5}=10\frac{3}{5}=10.6 \\ n=\lceil n_1\rceil =\lceil 10.6\rceil =11 \end{gathered}$$

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