Train A
124.7mph (124.7/60*8)=16.162mi
124.7mph/60mins*8(mins)
Train B
253mph (253/60*8)=33.7mi
33.7+16.16=49.89mi
252.5-49.89=203.61mi (left to travel)
124.7+252.5=377.2mph (combined speed)
203.61mi / 377.2mph =.539hrs (time to come together)
so 32 mins, so 10:08+32mins= 10:40