I tried this method at first…
Since I know the denominator of the fraction using combinations I include that first: $9C2$.
I am getting stuck at the numerator part of the fraction because there are only $3$ cases $\left(0,5;1,4;2,3,\right)$ right ?.
So the answer I get is $1/12$.
Is the correct? And does order matter in this case ?.
Best Answer
Bettween 10- 99 there are 90 two digit numbers. Of them 14,23,32,41,and 50 have sums adding to 5.
So the probability is $\frac 5{90} = \frac 1{18}$