Question

영어로 please help in English

A passenger jet can fly 1290 miles in three hours with a tail wind but only 1230 miles in three hours into a Herman. Find the speed of the jet in still air and the speed of the wind

Answer 1

The speed of the plane is 420 miles per hour and the speed of the wind is 10 miles per hour.

Answer 2

I only know English, so that's perfect :P

Explanation:

I'm going to guess... that "Herman" is really "headwind" and that this jet is flying into ( headwind) and with ( tailwind) the same wind... so the same velocity wind ( note I used the physics term velocity for the speed of the wind b/c the wind also has to have a direction... and we are saying it's direction and it's speed are constant)

so take the difference of the two distances... 1290 - 1230 = 60

we now know... that the difference in distance traveled is 60 miles, so 1/2 of that is what's gained or lost , by a tailwind or a headwind, so 30 miles is gained or last flying into the wind or with the wind.

also this is in 3 hours , how convenient, 30 / 3 = 10

the wind is 10 MPH

there fore.... the jet could fly 1260 miles in 3 hours with out any wind or

d = rt where d= distance , r= rate ( think speed) and t = time ( of course [ofc] )

1260 = r * 3 hours

420 = r

the jets speed is 420 MPH