Question 37851
Let the x be the speed for computer bus
Let x+25 be the speed for express bus
2x=0.75(x+25)
2x=0.75x+18.75
1.25x=18.75
x=15
15+25=40
Hence a computer bus travels at 15mph and the express bus travels at 40mph.
<pre><b>2.
Let x be the speed.
On going = x
On returning = x+30
Equation:
{{{40/x+40/(x+30)=2}}}
40[(x)+(x+30)]=2[(x)(x+30)]
{{{40(2x+30)=2(x^2+30x)}}}
{{{80x+1200=2x^2+60x}}}
{{{2x^2-20x-1200=0}}}
{{{x^2-10x-600=0}}}
Solve the quadratic system and you get:
x=30
Hence, the speed of the car is 30mph.
Paul.