Solve it if you can
Probability
Level
3
Find the number of positive numbers with three digits divisible by 5 such that the digits in each number are different.
The answer is 136.
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1 solution
We can use the product rule. We divide this exercise in 2 cases: the number of three digits which end with zero and the number of three digits which end with five( those are the only number which are divisible by 5). Numbers ending with 5= 8( you should exclude both 5 and 0)x8x1=64 Numbers ending with 0= 9x8( you should exclude zero and the number you used as first digit)x1= 72
The result will be 64+72