Explanation:As per divisibility rule

"A number is divisible by 3 if the sum of the digits is divisible by 3"Here,

73,_95 : the sum of the digits add up to = 24, which is divisible by 3, therefore, one possibility of the blank is 0

Since the sum of the digit adds up to 24 That means by adding 3 will provide the next number a multiple of 3 i.e the blank can be filled up by 0, 3, 6 and 9

Hence the probability that the resulting five-digit number will be a multiple of 3 = \(\frac{4}{10} = \frac{2}{5}\) (Total possibilities is 10 i.e from 0 to 9)

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