Answer:
[tex]t=280\ minutes[/tex]
Step-by-step explanation:
Let's call "v" the speed of the commercial airplane and call "t" at the travel time of the commercial plane
The distance in kilometers of the trip is: 1730 km
Then we know that:
[tex]vt=1730[/tex]
Then for the jet we have that the speed is:
[tex]2v[/tex]
The flight time for the jet is:
[tex]t-140[/tex]
Therefore:
[tex](2v)(t-140) = 1730[/tex]
Substituting the first equation in the second we have to:
[tex](2*\frac{1730}{t})(t-140) = 1730[/tex]
[tex](\frac{3460}{t})(t-140) = 1730[/tex]
[tex]3460-\frac{484400}{t} = 1730[/tex]
Now solve for t
[tex]\frac{484400}{t} = 3460 - 1730[/tex]
[tex]\frac{484400}{t} =1730[/tex]
[tex]\frac{t}{484400} =\frac{1}{1730}[/tex]
[tex]t=\frac{484400}{1730}[/tex]
[tex]t=280\ minutes[/tex]
