Question

if 51z3 is a multiple of 3 where Z is a digit what might be the values of Z​

Answer 1

add the digits 5,1,3,z

which comes=5+1+3+z

=9+z

now as we know the divisibility test of 3 is that "the individual digits of the number add up to be a multiple of 3."

since the digits add up to 9+z ,

then z can be that number which adds to 9 and forms a multiple of 3.

Hence , z can be 0,3,6 or 9....