Assuming they left at the same time and are traveling in the same direction:

distance = rate x time

First Plane

d = rt

rate = 1.5r {1.5 times as fast as second plane}

time = 9 {traveled for 9 hours}

d = 1.5r(9) {distance = rate x time}

d = 13.5r

Second Plane

d = rt

rate = r

time = 9 {traveled for 9 hours}

d = 9r {distance = rate x time}

In 9 hours, the first plane will be 387 miles in front of second plane.

13.5r = 9r + 387 {first plane equals second plane plus 387}

4.5r = 387 {combined like terms}

r = 86 {divided each side by 4.5}

**Rate of second plane is 86.**1.5r = rate of first plane

= 1.5(86) {substituted 86, in for r, into 1.5r}

= 129 {multiplied}

**129 mph is rate of first plane***- Algebra House
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