What x is added to each of 10, 16, 22 and 32, the numbers so obtained in this order are in proportion? What is the mean proportional between the numbers (x + 1) and (3x + 1)?
Answer & explanation
Correct answer: option 3
The numbers are x + 10, x + 16, x + 22, x + 32
The numbers are in proportion,
⇒ \(\frac{x + 10}{x + 16}\) = \(\frac{x + 22}{x + 32}\)
⇒ 320 + 10x + 32x = 352 + 38x,
⇒ 4x = 32
⇒ x = 8,
According to the question,
The mean proportion of (x + 1) and (3x + 1) = √(x + 1)(3x + 1)
⇒ √(9 x 25) = 15