$$\text{Set}\; = \{0,1,2,3,4,5,6\}$$
Find the probability that a three digit number which does not have the digit $0$ chosen at the far left and is chosen at random from the set, is NOT a multiple of 5.
$$P(\text{NOT A multiple of 5}) = \dfrac{6\cdot 7 \cdot 5}{6\cdot 7\cdot 7} = \dfrac{210}{294} = \frac{5}{7}$$
Is this correct?
Best Answer
It is perfectly correct, yes. Well done.
But in any "submitted" answer you might give, e.g., in an assignment or on a test, it would also be good to include a few words about how you arrived at your answer, or why you believe it is the answer. Oftentimes, the calculations "speak for themselves," and the reasoning is easily followed, but not always.