Question 1047167
One plane can travel 10 miles per hour faster than another.
 One of them goes 585 miles in the same time it takes the other to go 570 miles. What are their speeds?
:
let s = the speed of the slower plane
then
(s+10) = speed of the faster
:
Write time equation; time = dist/speed
{{{570/s}}} = {{{585/((s+10))}}}
Cross multiply
585s = 570(s+10)
585s = 570s + 5700
585 - 570s = 5700
15s = 5700
s = 5700/15
s = 380 mph is the speed of the slower plane
then obviously,
390 mph is the speed of the faster
:
;
Check this; Find the actual time of each, should be equal
570/380 = 1.5 hrs
585/390 = 1.5 hrs