Question 428014
rate x time = distance

time = distance/rate


Take speed without wind as s.
Those with wind and against wind times given as equal.


With the wind {{{435/(s+15)}}}

Against the wind {{{345/(s-15)}}}


Times were equal.
{{{435/(s+15)=345/(s-15)}}}
Solve this for s.


{{{435(s-15)=345(s+15)}}}

{{{87(s-15)=69(s+15)}}}

{{{87s-1305=69s+1035}}}

{{{(87-69)s=1305+1035}}}

{{{18s=2340}}}

{{{s=2340/18=1170/9=130}}}

130 miles per hour without the wind