Question

Which number should be subtracted from 12, 16 and 21 so that resultant numbers are in continued proportion?

Answer 1

Let the number to be subtracted be x. 

∴ (12 – x), (16 – x) and (21 – x) are in continued proportion.

∴ 84 – 4x = 80 – 5x

 ∴ 5x – 4x = 80 – 84 

∴ x = -4

∴ -4 should be subtracted from 12,16 and 21 so that the                                                      resultant numbers in continued proportion.