Which of these sets of numbers are in continued proportion?
(i) 0.4, 3.6, 3.24
(ii) 7, 21, 63
(iii) 2.4, 9.6, 38.4

Correct option is A

​$$\frac{0.4}{3.6} = \frac{4}{36} = \frac{1}{9}$$​​

​$$\frac{3.6}{3.24} = \frac{360}{324} = \frac{10}{9}$$​​

​$$\frac{7}{21} = \frac{1}{3}.$$​​

​$$\frac{21}{63} = \frac{1}{3}$$​​

​$$\frac{2.4}{9.6} = \frac{1}{4}$$​​

​$$\frac{9.6}{38.4} = \frac{1}{4}$$​​