Question

A jet flew for 2 hrs before strong head winds reduced its speed by 40mph. If it took the plane 5 hrs to travel 1,380 miles, find its speed before flying into the head winds.

Answer 1

As per the problem

A jet flew for 2 hrs before strong head winds reduced its speed by 40 mph.

It took the plane 5 hrs to travel 1,380 miles

Total time=5 hrs, Time of fly before headwinds$=2$,

Time of fly in headwinds$=5-2=3 hrs$

Let the speed before head winds $=v$

Then speed in headwinds$=(v-40)$

As we know that

$\text{Distance =Speed*Time}$

Hence using this formula and the given data we can write

$1380=2v+3(v-40)\\ \\ \text{Simplify we get}\\ \\ 3v-120+2v=1380\\ \\ 5v=1380+120\\ \\ 5v=1500\\ \\ v=300mph$

Hence speed before flying into the headwinds=300mph