Question

A private jet flies the same distance in 7 hours that a commercial jet flies in 5 hours. If the speed of the commercial jet was 99 mph less than 2 times the speed of the

private jet, find the speed of each jet.
Answer

Answer 1

• Private jet - 165 mph
• Commercial jet - 231 mph

Explanation:

Let the speed of the private jet is p and commercial jet is c.

Set equations

• 7p = 5c
• c = 2p - 99

Solve by substitution

• 7p = 5(2p - 99)
• 7p = 10p - 495
• 10p - 7p = 495
• 3p = 495
• p = 495/3
• p = 165

Find c:

• c = 2*165 - 99 = 330 - 99 = 231