Please help me by solving this!​

Ani age is 21

Biju age is 18

Step-by-step explanation:

let Ani age be X

let Biju age be Y

the difference of their age is 3

i.e X - Y = 3,(equ. 1)

let Dharam age be A

let Cathy age be B

i.e A = 2x

B = y/2

the difference of their age is 30

Y/2 - 2x = 30 (equ. 2)

from equ.1 X = ( 3+y)( equ.3)

y/2 - 2(3+y) = 30

y/2 - 6 + 2y = 30

multiply both side by 2

y - 6 + 2y = 60

y + 2y = 60 - 6

3y = 54

Y = 18

from equ.3

X = 3+Y where y is 18

X = 3+18 = 21

the answer is; biodiversity resulting from few ancestors

adaptive radiation occurs when a population is subjected to a large natural environment with spatial ecological variations. the parts of the population in the different ecologies begin to adapt to their local environments. due to non-random mating across the large populations, this causes the different populations from the large population to speciate within their local environments. they, therefore, diverge to different species sharing a common ancestor.  

the answer is:

mean: 6

mad: 2.14