What should be added to each of the four numbers 5, 19, 7 and 25 to make them proportional?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 2.
Let x be added to each number. Then:
⇒ (5 + x) / (7 + x) = (19 + x) / (25 + x)
Cross-multiply:
⇒ (5 + x)(25 + x) = (19 + x)(7 + x)
⇒ 125 + 30x + x² = 133 + 26x + x²
⇒ 4x = 8
⇒ x = 2