Question

Two cities are 1580 miles apart. A plane leaves one of them traveling towards

the other at an average speed of 400 miles per hour. At that time a plane leaves
the other traveling towards the first at an average speed of 390 miles per hr.
How long will it take them to meet?

Answer 1

Explanation:

City A to City B : 1580 miles

Plane speed (C) to City B from A : 400 miles per hour

Plane speed (D) to City A from B : 390 miles per hour

Time taken for plane (C) :

=1580 ÷ 400

=3⁹/²⁰ hours

Time taken for plane (D) :

=1580 ÷ 390

=4²/³⁹ hours

Finding time difference

= 4²/³⁹ - 3⁹/²⁰

=469/780

Finding midpoint

= 469/780 ÷ 2

=469/1560

Total

= 3⁹/²⁰ + 469/1560

= Aprroximately 3¾ hours

Answer 2

Explanation:

2 hour