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In how many ways can a Quality Analyst team of 20 members be made from 6 Hindi experts, 5 English Experts, 16 Science experts and 15 other subjects’ experts among whom 5 experts are absent and 2 specified experts must always be included in the team?

Option: 1

\frac{35!}{18!17!}


Option: 2

\frac{55!}{18!17!}


Option: 3

\frac{35!}{19!17!}


Option: 4

Cannot be determined


Answers (1)

best_answer

Note the following:

  • The formula for the combination for the selection of the items\mathrm{x} from the \mathrm{y} different items is \mathrm{=^{y}C_{x}=\frac{y!}{x!\left ( y-x \right )!}}

  • The combination for the selection of the items \mathrm{r} from the \mathrm{n} different items with \mathrm{k} particular things always included and \mathrm{h} particular things always excluded is \mathrm{^{n-k-h}C_{r-k}}

Since 5 experts are absent and 2 specified experts must always be included in the Quality Analystteam, the following is evident.

  • The number from which the restricted combination is to be made is .

          \mathrm{=n-k-h=(6+5+16+15)-2-5=42-7=35}

  • The number with which the restricted combination is to be made is

           \mathrm{=r-k=20-2=18}

Therefore, the required restricted combination is

\mathrm{=^{n-k-h}C_{r-k}}

\mathrm{=^{35}C_{18}}

\mathrm{=\frac{35!}{18!17!}}

Posted by

Anam Khan

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