Question

The ratio of the third proportional to 9 and 15 and the mean proportional to 16 and 25 is?

• A. 30
• B. 40
• C. 12
• D. 50
• E. none

Answer 1

The correct option is C

12

$\frac{9}{15}=\frac{x}{20}$so x=12 [m=mean proportion, 16/m=m/25, therefore m = 20]