Two trains of equal length take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction?

Options

A. 16
B. 15
C. 12
D. 10

Answer

C

Explanation

अभीष्ट समय `=("कुल दूरी ")/("आपेक्षिक चाल")`
`=(120+120)/((120)/(10) +(120)/(15))`
` =( 240 )/(12+8)=12 ` सेकण्ड