Use proportions to figure this out. On the top you'll have miles and on the bottom you'll have minutes. I am going to change 3/4 to .75 and 1/8 to .125:
We want to know how many miles per 1 minute that is. So we have the unknown on top in a new ratio, with 1 on the bottom:
This second ratio is allowing us to calculate what the decimal ratio is in miles per 1 minute. Cross multiply to get
.125x = .75 so
x = 6 miles
That tells us that the decimal ratio is equivalent to 6 miles per minute
Since it is stated that angle x forms a straight line with the 50 and 50 degree angles, and that angle x is vertical to angle y, we can do 40+50+y=180 to find angle Y.