me thank yu tri tu sae:
traen go 250 MILES at konstant speed
This time it slo down tu 80% av normal aft it go 103 miles
As a result, it take 70 minuts longer...maebee yu wanna yuze 1.66666666 ours
normal time=250/speed1
nu time=(103/speed1) +[147/(0.8*speed1)]=normal+70 minuts...=(250/speed1)+70
become: 103 +(147/0.8)=250 +70*speed1...or 1.666666*speed1
103+183.75 -250=70*speed1...or 70*speed1=286.75 -250=36.75
speed1=36.75*70=2572.5...or 36.75 miles/1.66666666 ours=22.05 MPH
22/0.8=27.5625 MPH
250/27.5625=9.07 ours...original speed & time