Question

If 5:4 and x:16 are in proportion, then what is the value of x?

Answer 1

Here the extremes are 5 and 16 and the means are 4 and x.
Product of extremes = 5 × 16 = 80.
Product of means = x × 4 = 4x.
Thus by proportionality law, the product of extremes = product of means.
4x = 80
x = 80/4
Hence, x = 20.