What number must be added to each of the numbers 6 15 20 and 43 to give four numbers in proportion?

Let the number added to be x.

therefore,

hence, the required number which should be added is 3.

What least number must be added to each of the numbers 6, 15, 20 and 43 to make them proportional?

Let the number added be x.

∴ (6 + x) : (15 + x) :: (20 + x) (43 + x)

`=> (6+x)/(15 + x) = (20 + x)/(43 + x)`

⇒ (6 + x)(43 + x) (20 + x)(15 + x)

`=> 258 + 6x + 43x + x^2 = 300 + 20x + 15x + x^2`

`=> 49x - 35x = 300 - 258`

`=> 14x = 42`

`=> x = 3`

Thus, the required number which should be added is 3.

Concept: Concept of Proportion

  Is there an error in this question or solution?