Which of the following is the lowest ratio ?
A
7 : 15
B
15 : 23
C
17 : 25
D
21 : 39
Correct Answer: 7 : 15
$$\eqalign{ & \Rightarrow 7:15 = \frac{7}{{15}} = 0.466 \cr & \Rightarrow 15:23 = \frac{{15}}{{23}} = 0.652 \cr & \Rightarrow 17:25 = \frac{{17}}{{25}} = 0.68 \cr & \Rightarrow 21:39 = \frac{{21}}{{39}} = 0.538 \cr} $$Clearly, 7 : 15 is the lowest
