Solution:
We know that, the odd numbers are
{1,3,5,7,9}
∴‌‌n(a)=5
Divisible by 3 are {0,3,6,9},n(b)=4
Even numbers are {0,2,4,6,8},n(c)=5
and prime numbers are {2,3,5,7},n(d)=4
∴ Four-digit numbers abcd exist
=5â‹…4â‹…5â‹…4
=400
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