Question

two planes leave atlanta at 3 pm EST. one flies east and travels at a speed of 75 kilo. per hour slower than the other plane witch is flying west. by 7 pm EST the plane are 5460 kilo. apart. what is the speed of the plane flying east

Answer 1

Let us start with the plane flying east at a slower speed. Let us assume that its speed is x kilometers per hour. After 4 hours, it will have traveled 4*x = 4x kilometers. Now let us calculate the speed of the plane flying west. It is faster by 75 kilometers per hour than the other plane. So its speed per hour is x+75 kilometers per hour. After 4 hours, it will have traveled 4( x+75) = 4x+300 kilometers. The total distance traveled by both the planes is 5460 kilometers. In other words, 4x+4x+300 =5460 kilometers. Now simplify the equation: 8x + 300 = 5460 8x = 5460 - 300 8x = 5160 x = 5160/8 645. x is the speed of the plane flying east. It is 645 kilometers. x + 75 is the speed of the plane flying west. It is 645 + 75 = 720 kilometers.