Question:
The total number of positive integral solutions (x, $y, z$ ) such that $x y z=24$ is :
Correct Option: , 4
Solution:
$x y z=2^{3} \times 3^{1}$
Let $x=2^{\alpha_{1}} \times 3^{\beta_{1}}$
$y=2^{\alpha_{2}} \times 3^{\beta_{2}}$
$\mathrm{z}=2^{\alpha_{1}} \times 3^{\beta_{2}}$
Now $\alpha_{1}+\alpha_{2}+\alpha_{3}=3$.
No. of non-negative intergal sol $={ }^{5} \mathrm{C}_{2}=10$
$\& \beta_{1}+\beta_{2}+\beta_{3}=1$
No. of non-negative intergal soln $={ }^{3} \mathrm{C}_{2}=3$ Total ways $=10 \times 3=30$.