line 15 C = A * B

[ghost]

This returns an error. Is the line meant to be C = A .* B?

[abavoil]

30-Days-Of-Julia/day-4.jl

Line 14 in 6886879

B = [7 8; 9 10; 11 12]

is meant to be B = [7 8 9; 10 11 12] since A is explicitly a 3 by 2 matrix and the matrix multiplication $AB$ is defined if and only if the number of columns of $A$ (2) is equal to the number of rows of $B$ (should be 2 instead of 3).