A train Express A leaves Delhi at 5 a.m and reaches Mumbai at 9 a.m.Another train Express B leaves Mumbai at 7 a.m and reaches Delhi at 10.30 a.m.At what time do they cross each other after 7 a.m ?
Speed of Express A = x/4kmph
Speed of Express B = 2x/7kmph =>(t=3.30 = 3(1/2) = 7/2)
Trains will meet T hours after 7 a.m
(x/4)(y+2) + (2x/7)y = x
(y+2)/4 + (2y/7) = 1
(7y+14+8y)/28 = 1
15y = 28-14
Y =(14/15)×60 = 56 min
help me uderstand this