We can transform each of the options for 'n' years. (997)214+3≡(p−3)2n−1+3(1003)215+6≡(p+3)2n+6(1003)215−3≡(p+3)2n−3(997)15−3≡(p−3)n−3 As per the condition, in one year, the population ' p′ becomes ′3+2p′ Putting the value of n=1 in each option, and checking to get 3+2p, we have (p−3)2n−1+3≡3=3+2p
(p+3)2n+6≡(p+3)2+6=3+2p(1003)215−3≡(p+3)2−3=3+2p
(p−3)n−3≡(p−3)−3=p−6 Hence, the right answer is option 3.