This thread really helped me understand all the probability stuff. The answer to your question is towards the bottom.there is 70% chance of rain each day for 3 days. what is prob it will rain 2 days out of 3 days?
--- can someone explain how to solve this??
You got those mixed up. Combo is order doesn't matter.You are asking the difference between permutation and combination.
permutation is the same award. Let's say the first 3 girls entering my room will get to have the same awards, that's permutation.
1st girl entering my room can stay 1 hr, 2nd girl can stay 30 min, 3rd girl can stay 1 min, this refers to 3 diff awards so this is combination.