please help me with this maths question

moores law states that the number of transistors on an intergrated circuit will double every 18 months can be expressed as

P = Po * 2t/18

wher Po is the number of transistors on a circuit and P is the number of transistors t months after the Po

if the number on a intergrated circuit was 4000 in 1971

calculate:

(i)the number of transitors in 1980

(ii)when did the numbers of transitors break the 1,000,000 mark?

thank you for any help

p.s i already think i know how to do this but i cant be 100% sure