You can always use the formula to solve out the percentage.
(n / 100) x d = a
If I subtitute,
(150 / 100) x d = 3
-> 1.5 x d = 3
-> d = 3 / 1.5
-> d = 2
Therefore, 2% of 150 is 3.
Hope it helped!
$${\frac{{\mathtt{3}}}{{\mathtt{150}}}}{\mathtt{\,\times\,}}{\mathtt{100}} = {\mathtt{2}}$$
2%
Yes it is that easy. :)