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In how many ways can a daily revision routine of at least one chapter of each subject be made from 12 Mathematics chapters, 5 Science chapters, 6 History chapters and 11 English chapters?

Option: 1

2^3\left(2^2+1\right)\left(2^3+3\right)
 


Option: 2

2^3\left(2^2+1\right)\left(2^2+3\right) 3^2
 


Option: 3

\left(2^2+1\right)\left(2^3+3\right) 3^2
 


Option: 4

2^3\left(2^2+1\right)\left(2^3+3\right) 3^2


Answers (1)

best_answer

Note the following:

  • The formula for the combination for the selection of the \mathrm{x} items 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 none or more items from the \mathrm{n}identical items is \mathrm{=n+1}

From the available data, the following is evident. 

  • The combination for the selection of the one or more Mathematics chapters is =12

  • The combination for the selection of the one or more Science chapters is =5

  • The combination for the selection of the one or more History chapters is =6

  • The combination for the selection of the one or more English chapters is=11

Therefore, the required combination for selection of at least one chapter of each subject is

=12\times5\times6\times11

=2^{2}\times3\times5\times2\times3\times11

=2^{2}\left ( 2^{2}+1 \right )\left ( 2^{3} +3\right )3^{2}

 

Posted by

shivangi.bhatnagar

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