Birds

MBA.Aspirant wrote:

pemdas wrote:
(50-20)/80=30/80=3/8

Explain the reasoning behind it pls

pemdas is essentially saying that, since the question is asking for a percent, we don't need to consider the actual numbers of birds.

In fact, if we're going to use numbers, let's say there are 100 birds.

This means that 20 are tagged and 80 are untagged.

For 1/2 the birds to be tagged, we need 50 tagged birds. In other words, we need 30 additional tagged birds.

So, from the 80 untagged, we need to tag 30 birds.

30/80 = 3/8 = 37.5%

Cheers,
Brent