Question

What number should be subtracted from each of the numbers 23, 30, 57 and 78 so that the resultant numbers are in proportion ?

• A. 4
• B. 3
• C. 6
• D. 7

Answer 1

Answer:

C. 6

Consider x to be the number to be subtracted from each term So, 23–x, 30–x, 57–x and 78–x are proportional (23–x) : (30–x) :: (57–x) : (78–x) (23–x)(78–x) = (30–x)(57–x) 1794 - 23x - 78x + x² = 1710 - 30x - 57x + x² 1794 - 101x + x² = 1710 - 87x + x² 14x = 84 x = 6