Question 204461
Simply draw up a two dimensional table in which the left hand side represents bag 1 and the top represents bag 2. Any cell is simply the sum of its corresponding left side and top side.


<table border=1><th></th><th><font color=red>1</font></th><th><font color=red>2</font></th><th><font color=red>3</font></th><th><font color=red>4</font></th><th><font color=red>5</font></th></tr><tr><th><font color=red>1</font></th><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td></tr><tr><th><font color=red>2</font></th><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td></tr><tr><th><font color=red>3</font></th><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td></tr><tr><th><font color=red>4</font></th><td>5</td><td>6</td><td>7</td><td>8</td><td>9</td></tr><tr><th><font color=red>5</font></th><td>6</td><td>7</td><td>8</td><td>9</td><td>10</td></tr></table>


Note: the red values represent the numbers on the balls and the black values are the sums.



Now looking at the table, we can see that there are only 2 sums of 9 (namely 5 and 4 or 4 and 5). Since there are a total of 25 possible sums (5*5=25), this means that the probability is {{{2/25}}} or 0.08 in decimal form (which is an 8% chance).