Since there is no condition whatsoever for this arrangement, I can consider the 2 digits and the 5 letters as 7 different objects.
Total permutation (with no repetition):
7 chosen among 7 , that is 7 ! = 5040 arrangements
Total permutation (WITH REPERTITION):
7⁷ = 823 543
1. Check the tree diagram in the picture attached.
2. The blue segment represents "on time"
The red segment represents "not on time"
3. blue - blue - red represents the case 1st on time, 2nd on time, 3rd not on time.
the combined probability is 90/100*90/100*10/100=9/10*9/10*1/10=99/1000=0.099
4. Remark with a tree diagram we can tell anything asked about the probability of an experiment.
6+0=6
When you add any number to 0, that number stays the same since you aren’t adding anything to it. So the answer is 6.