Train P crosses a pole in 30 seconds and train Q crosses the same pole in one minute and 15 seconds. The length of train P is three-fourths the length of train Q. What is the ratio of the speed of train P to that of train Q? Choose the correct choice from the following choices
A) 15 : 8 B) 14 : 8 C) 17 : 8 D) 13 : 8 E) 12 : 8
A   15 : 8   Given that train P crosses a pole in 30 seconds and train Q crosses the same pole in one minute and 15 seconds.   Let the length of train P be LP and that of train Q be LQ   given that LP = 3/4 LQ   15 : 8s the train P and Q crosses the pole in 30 seconds and 75 seconds respectively,   =&gt; Speed of train P = VP = LP/30   Speed of train Q = VQ = LQ/75   LP = 3/4 LQ   =&gt; VP = 3/4 LQ/(30) = LQ/40   Ratio of their speeds = VP : VQ   = LQ/40 : LQ/75 =&gt; 1/40 : 1/75 = 15 : 8
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Train P crosses a pole in 30 seconds and train Q crosses the same pole in one minute and 15 seconds. The length of train P is three-fourths the length of train Q. What is the ratio of the speed of train P to that of train Q?