Answer:
Speed of train A is 44 miles/hr.
Step-by-step explanation:
Let the speed of train A = [tex]u\ miles/hr[/tex]
Let the speed of train one = [tex]v\ miles/hr[/tex]
Train A travels at [tex]\frac{4}{5}^{th}[/tex] the speed of train one.
i.e.
[tex]u = \dfrac{4}{5}v \\\Rightarrow v =\dfrac{5}{4}u.... (1)[/tex]
Distance traveled = 693 miles
Time taken = 7 hours
They are travelling in opposite directions so the resultant speed will appear to be faster.
Relative speed = [tex]u+v\ miles/hr[/tex]
The trains are 693 miles apart in 7 hours that means they have traveled a total distance of 693 miles in 7 hours with a speed of ([tex]u+v[/tex]) miles/hr.
Using the formula:
[tex]Speed = \dfrac{Distance}{Time}[/tex]
[tex]u+v = \dfrac{693}{7}\\\Rightarrow u+v=99 ...... (2)[/tex]
Putting the value of v using equation (1):
[tex]\dfrac{5}4u+u=99\\\Rightarrow 5u+4u = 99 \times 4\\\Rightarrow 9 u = 99 \times 4\\\Rightarrow u = 11 \times 4 = \bold{44\ miles/hr}[/tex]
Speed of train A is 44 miles/hr.
