Probability doubt

Approach requiredIMG-20191107-WA0008

19P=9 is answer
If it is correct I will send the solution.

Incorrect

18 is answer

Incorrect.

5

Incorrect

15731964660847700866920138891551
4 is the answer ??

15731971868607775379900312068598

15731972171096390434953155544866

Hope it helps

Yes it is 4,Thanks
Last step was particularly smart
I did it too last night but by using multinomial

pls share ur method