The number of non-negative integral solutions of $\mathrm{x}_1+\mathrm{x}_2+\mathrm{x}_3+\mathrm{x}_4=10$ is

The number of non-negative integral solutions of $\mathrm{x}_1+\mathrm{x}_2+\mathrm{x}_3+\mathrm{x}_4=10$ is
  1. $120$
  2. $144$
  3. $256$
  4. $286$

Solution

Given $x_1+x_2+x_3+x_4=10$ Now non-negative solution $\begin{aligned} & ={ }^{10+4-1} C_{4-1} \\ & ={ }^{13} C_3=\frac{13 \times 12 \times 11}{3 \times 2}=286 \end{aligned}$

Asked in: AP EAMCET 2023 (15 May Shift 2)

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