Find 2 numbers such that their mean proportion is 25 and their third proportion is 25.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 25 and 25.
Let the two numbers be a and b.
According to the given question,
(a + b)/2 = 25
⇒ a + b = 50 ...(i)
Also, b2/a = 25
⇒ a = b2/25 ....(ii)
Putting value from equation (ii) in equation (i),
⇒ b2/25 + b = 50
⇒ b2 + 25b - 1250 = 0
⇒ b2 + 50b - 25b - 1250 = 0
⇒ b(b + 50) - 25(b + 50) = 0
⇒ b = -50; b = 25
Now, a + 25 = 50
⇒ a = 25