Hey there! I'm happy to help!
Train X takes out 1/4 of our journey.
Now, we have 3/4 of the journey left.
Train Y takes 3/4 of the last 3/4 of the journey. How much is that, let's just multiply the fractions!
3/4*3/4= 9/16
So, 9/16 of the total journey is done by Train Y.
A fourth of 16/16 is 4/16, so that leaves us with 3/16 left to go.
So, 3/16 of our total distance is equal to 10 km. Let's call our total distance d and set this up as an equation.
3/16d=10
Divide both sides by 3/16.
d= 53 1/3
We also remember that Train Y gave us 9/16 of our total journey, so we can multiply this by our total distance to see how far train Y went.
53 1/3 * 9/16= 30
So, A. Ahmad traveled 30 miles by Train Y and B. his total distance traveled is 53 1/3 miles.
Have a wonderful day and keep on learning! :D