Question 889594
(3*r)^2+(3*(r-40))^2=600^2
r=160  flight 237
r-40=120 flight 875
check
(3*160)^2+(3*120)^2=600^2
230400+1296000=36000
ok

see also
http://www.algebra.com/algebra/homework/word/travel/Travel_Word_Problems.faq.question.860155.html