Question

in a zoo, the ratio of horse to zebra was 3 : 4. when 1 new horse is added, the ratio of horse to zebra becomes 4:5 . how many horses and how many zebras are there in the zoo?

Answer 1

No. of horses 3x and No. of Zebras 4x.... New horse added to the group= 3x+1... New ratio of horses to yhe Zebras= 3x+1 ÷ 4x= 4÷5= 5(3x+1)= 4(4x)....therefore 15x+5 = 16x...then 16x-15x=5.....1x=5....x=5..... The no. of Zebras are 4×5= 20.....

Answer 2

There are 15 horses and 20 zebras in the zoo.

Let there be 'h' no. of horses and 'z' no. of zebras.

From the first part, the ratio of horses to zebras was 3:4. So, we can represent this as:

h : z = 3 : 4

⇒h/z = 3/4

⇒3z = 4h

⇒z = (4/3)h          ...(1)

From the second part, it is told that when 1 new horse is added, the ratio of horse to zebra becomes 4:5. So,

horses now = (h+1)

So, (h+1) : z = 4 : 5

⇒ 4z = 5(h+1)

⇒ 4(4/3)h = 5h + 5                   [Replacing the value of z from (1)]

⇒ 16h = 3(5h + 5)

⇒ 16h - 15h = 15

⇒ h = 15

No. of horses are 15

Putting the value of h in (1),

z = (4/3) × 15 = 20

No. of zebras are 20.