A box contains 100 tickets numberd 1. 2, 100. Two tickets are choosen at random. It is given that the maximum number on the two choosen tickets is not more than 10. The minimum number on them is 5 with probability  is

Let A be the event that maxirnum number on the two chosen tickets is not more than 10. and B is the event that mininurn number on them is 5

$A\cap B$ contains one number 5 and other greater than 5 and $\le 10$

$n(A\cap B){=}^5{C}_1=5\text{ and }n\left(A\right){=}^{10}{C}_2=45$

Thus.   $\frac{P(A\cap B)}{P\left(A\right)}=\frac{n(A\cap B)}{n\left(A\right)}=\frac{1}{9}$