On a tree, there are some parrots and some pigeons in the ratio of 7 : 9, respectively. After an hour, 8 parrots fly away, and 6 pigeons and 10 sparrows come and sit on the tree. The ratio of the parrots and the pigeons on the tree now is 1 : 4. What is the ratio of the parrots and the sparrows that are now on the tree?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e 3 : 5
On a tree, there are some parrots and some pigeons in the ratio of 7: 9, respectively.
Let's assume the number of parrots and pigeons initially is 7y and 9y.
After an hour, 8 parrots fly away, and 6 pigeons and 10 sparrows come and sit on the tree.
Now number of parrots = (7y-8)
number of pigeons = (9y+6)
number of sparrows = 10
The ratio of the parrots and the pigeons on the tree now is 1 : 4.
On a tree, there are some parrots and some pigeons in the ratio of 7: 9, respectively.
Let's assume the number of parrots and pigeons initially is 7y and 9y.
After an hour, 8 parrots fly away, and 6 pigeons and 10 sparrows come and sit on the tree.
Now number of parrots = (7y-8)
number of pigeons = (9y+6)
number of sparrows = 10
The ratio of the parrots and the pigeons on the tree now is 1 : 4.
⇒ (7y - 8)/(9y + 6) = 1/4
⇒ 28y - 32 = 9y + 6
⇒ 28y - 9y = 32 + 6
⇒ 19y = 38
⇒ y = 2
Ratio of the parrots and the sparrows now on the tree = (7y - 8) : 10
= (7 x 2 - 8) : 10
= (14 - 8) : 10
= 6 : 10
= 3 : 5