ANSWER
The plane will travel
[tex]457.2 \: miles.[/tex]
in 3 hours.
EXPLANATION
It was given that, the plane traveled at a constant speed and covered 762 miles in 5 hours.
So we can write the ratio,
[tex]5:762[/tex]
Let
[tex]x[/tex]
be the distance covered by the plane in 3 hours at the same speed.
Then we can again write the ratio,
[tex]3:x[/tex]
We can now write the proportional relation,
[tex]5:762 = 3:x[/tex]
We rewrite the ratios as fractions to obtain,
[tex] \frac{5}{762} = \frac{3}{x} [/tex]
We cross multiply to get,
[tex]5x = 3 \times 762[/tex]
We divide both sides by 5 to get,
[tex]x = \frac{3 \times 762}{5} [/tex]
[tex]x = 3 \times 152.4 [/tex]
This simplifies to,
[tex]x = 457.2 \: miles.[/tex]
