tuf ques

imo 7/12

whats OA?

you posted ques in both forums?

i wrongly posted there. Sorry
But. i am very confused with the statement ans ratio def given at last. why need that
OA is 7/12
you pls explain ur ans

let the total numnber of geese be x
total male = 0.3x, total female = 0.7x

let those migrated be y
num of male migrated = 0.2y
number of female migrated = 0.8y

male migration ratio = 0.2y/0.3x = 2y/3x

female migration ratio = 0.8y/0.7x = 8y/7x

male ratio/female ratio = [2y/3x]/[8y/7x] = 2y*7x/8y*3x = 7/12

Try picking numbers.

Lets say ther eare 100 geese in total

30 are male
70 are female.

Pick a number (easy to work with with division/multiplication etc..) lets say 80 geese migrated

20% of 80 were male i.e 20/100*80 = 16
64 were female(remaining 80%)

So No of males migrated to No of female migrated
= (Migrated male geese / Total male geese) / (Migrated Female geese / Total Female geese)

= 16/30 / 64/80
= 16/30 * 80/64
= 7/12

Corrected typo in previous post (in bold)

Try picking numbers.

Lets say ther eare 100 geese in total

30 are male
70 are female.

Pick a number (easy to work with with division/multiplication etc..) lets say 80 geese migrated

20% of 80 were male i.e 20/100*80 = 16
64 were female(remaining 80%)

So No of males migrated to No of female migrated
= (Migrated male geese / Total male geese) / (Migrated Female geese / Total Female geese)

= 16/30 / 64/70
= 16/30 * 70/64
= 7/12

ans: 7/12