In an imaginary planetary systam, the centrel star has the same mass as our sun, but is much brighter so that only a planet twice the distance between the Earth and sun can support life. According to bilogical evolution (including aging processes etc.) on that planet similar to ours, what would be the average life span of a 'human' on that planet in terms of its natural life ? The average life span of a human on the Earth may be taken to be `70` years.

Explanation

`T_(2) = T_(1) ((R_(2))/(R_(1)))^(3//2) = T_(1) ((2R_(1))/(R_(1)))^(3//2) = 2 sqrt(2) T_(1)`
It means `2 sqrt(2)` years of earth are equal to 1 natural year of the imaginary planet.
`:. 1` year of earth `= (1)/(2(sqrt(2))` planet year.
`:.` Age of human `= 70` years of earth `= (70)/(2(sqrt(2))`
`= 24.75` planet years