Question 352564
let speed of bus be x mph
if it travels 10 mph faster then its speed = x+10 mph.
distance = 150 miles.
time taken with original speed - time taken with increased speed = 1/2 hour
...
time = distance /speed
150/x - 150/(x+10)= 1/2
LCM = x(x+10)
150(x+10)-150x/x(x+10) = 1/2
150x+1500 -150x = x(x+10) / 2
1500 *2 = x^2 +10x
x^2+10x-3000 =0
x^2+60x-50x-3000=0
x(x+60)-50(x+60)=0
(x+60)(x-50)=0
x=50 mph the original speed.

,,,
m.ananth@hotmail.ca