Answer:
Here, given
present population = 20000
according to question,
population gets double every 34 years
i.e P = 20000 × 2
= 40000
now,
P = 40000
T = 68-34 = 34
ie, again p is double
so, P = 40000×2
= 80000
Hence, the population after 68 years from now is 80000