In a monthly test, the teacher decides that there will be 3 questions, one from each exercise 7,8 and 9 of the text book. If there are 12 questions in exercise 7, 18 in exercise 8, and 9 in exercise 9, in how many ways can 3 questions be selected.

Dear Student,

Please find below the solution to the asked query:
$$\begin{gathered} 1 \mathrm{questions} \mathrm{from} \mathrm{each} \mathrm{exercise} 7,8,9 \\ \mathrm{In} \mathrm{Exercise} 7 \mathrm{there} \mathrm{are} 12\mathrm{ways} ,\mathrm{In} \mathrm{Exercise} 8 \mathrm{there} \mathrm{are} 18\mathrm{ways} , \mathrm{In} \mathrm{Exercise} 9 \mathrm{there} \mathrm{are} 9 \mathrm{ways} \\ \mathrm{So} \\ \mathrm{by} \mathrm{the} \mathrm{fundamental} \mathrm{principle} \mathrm{of} \mathrm{counting} , \mathrm{three} \mathrm{questions} \mathrm{can} \mathrm{be} \mathrm{selected} \mathrm{as} \\ 12\times 9\times 18=1944 \mathrm{ways} \end{gathered}$$

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