(a) We have to convert 3:1 into percentage:

So, Total parts = 3 + 1 = 4

Therefore,

First part = × 100 %

= 75 %

And,

Second part = × 100 %

= 25 %

(b) We have to convert 2: 3: 5 into percentage:

So,

Total parts = 2 + 3 + 5 = 10

Therefore,

First part = × 100 %

= 20 %

And,

Second part = × 100 %

= 30 %

Also,

Third part = × 100 %

= 50 %

(c) We have to convert 1: 4 into percentage:

So,

Total parts = 1 + 4 = 5

Therefore,

First part = × 100 %

= 20 %

And,

Second part = × 100 %

= 80 %

(d) We have to convert 1:2: 5 into percentage:

So,

Total parts = 1 + 2 + 5 = 8

Therefore,

First part = × 100 %

= 12.5 %

And,

Second part = × 100 %

= × 100 %

= 25 %

Also,

Third part = × 100 %

= 62.5 %