Question

Two planes make a 1750 mile flight, one flying 75 miles per hour faster than the other. The quicker plane makes the trip 3 hours faster. How long did it take the slower plane to complete the flight?

Answer 1

Answer:

The slower plane is flying at 175 miles per hour and complete the trip in 10 hours

The faster plane is flying at 250 Miles per hour and complete the trip in 7 hours

Step-by-step explanation:

Let s= speed of the slower plane s+75= speed of the faster plane

The time it takes the slower plane to make the flight = 1750/s

The time it takes the faster plane to make the flight is=1750/(s+75)

The difference in these two times is 3 hours

1750/s - 1750/(s+7)=3

{(s+75) / (s+75) * (1750/s)} - {(s/s) * (1750/s+75)} =3

(1750s+131250 / s^2+75s) - (1750s/s^2+75s) =3

1750s+131,250-1750s / s^2+75d =3

131,250 / s^2+75s = 3

Cross product

131,250=3(s^2+75s)

131,250=3s^2+225s

43,750=s^2+75s

s^2+75s-43,750=0

Solve the quadratic equation

x= -b +or- √b^2-4ac / 2a

a=1

b=75

c= -43750

x= -b +or- √b^2-4ac / 2a

= -75 +or- √(75)^2 - (4)(1)(-43750) / (2)(1)

= -75 +or- √(5625) - (-175,000) / 2

= -75 +or- √180625) / 2

= -75 +or- 425 / 2

x= -75 + 425/2 OR -75- 425/2

=350/2 OR -500/2

x=175 OR -250

We will ignore the negative sign because the planes are not flying Backward

The slower plane is flying at 175 miles per hour and complete the trip in 1750/175= 10 hours

The faster plane is flying at 250 Miles per hour and complete the trip in 1750/250= 7 hours