10 horses can graze a field in 14 days, and 10 sheep take 28 days to graze the same field. How many days will 5 horses and 10 sheep take to graze the same field?

10 horses can graze a field in 14 days, and 10 sheep take 28 days to graze the same field.

$$10H \times 14 = 10S \times 28$$

H = 2S    Eq.(i)

Let's assume 5 horses and 10 sheep take 'y' days to graze the same field.

$$(5H+10S)y = 10S \times 28$$

Put Eq.(i) in the above equation.

$$(5\times2S+10S)y = 10S \times 28$$

$$(10S+10S)y = 10S \times 28$$

20Sy = 280S

y = 14 days

So 5 horses and 10 sheep take 14 days to graze the same field.