Let x be the mean proportional between 25.6 and 32.4 and y be the third proportional to 32 and 48. Then 3x : 2y = ____.
Answer & explanation
Correct answer: option 2
Mean proportional (X) = \(\sqrt {25.6 x 32.4 }\)
⇒ X = 28.8
Third proportional (Y) = 32 : 48 : Y
⇒ 32Y = 48 x 48
⇒ 32Y = 2304
⇒ Y = 72,
⇒ 3x : 2y = 3(28.8) : 2(72) = 86.4 : 144 = 3 : 5