a 600 meter long train crosses a signal post in 40 seconds . how long will it take to cross a 18 kilometer long bridge , at the same speed ?
"s = 600 / 40 = 15 mps s = 18000 / 15 = 1200 sec = 20 min . answer : b"
divide(divide(multiply(18, const_1000), speed(600, 40)), const_60)