speed of plan is 20kmph less than 5 times speed of train p=5r-20
we notice that 160 times 4.5=720 times first equaton by 4.5
720=4.5rt 720=pt set equal 4.5rt=pt divide both sides by t 4.5r=p sub </span><span>p=5r-20 for p 4.5r=5r-20 minus 4.5r from both sides 0=0.5r-20 add 20 to both sides 20=0.5r times 2 both sides 40=r
sub back</span><span> p=5r-20 p=5(40)-20 p=200-20 p=180