Find the number of pairs $(z_1,z_2)$ of complex numbers such that: $z_1 z_2$ is pure imaginary $\frac{z_1}{z_2}$ is real $|z_1|

30.5*10=350$

you have to multiply the number without the decimal point then add it later but if its tenn u must move the place value of the decimal point 1 to the right.