What is the smallest number that should be added to 40 so that the result is the third proportional to 16 and 28?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 9.
Let the required number be x.
Third proportional to 16 and 28 means = 16 : 28 = 28 : (40 + x)
So, 16 × (40 + x) = 28 × 28
⇒ 640 + 16x = 784
⇒ 16x = 144
⇒ x = 9