I will help you on two conditions: 1) that you never again call yourself "stupid," and that you ask no more than 1 or 2 questions per post.
I'll focus on #5. Recall that distance = rate times time: d = r*t.
You want distance and are given rate and time: rate 1.8 km/min; time 48 min.
I see you write "distance" next to "1.8 km;" that is not correct, because
the problem states that "the rate is 1.8 km per minute." 1.8 km is a distance; 1.8 km / min is not (it's a rate).
So, again, to find the distance traveled, mult. the rate by the elapsed time:
distance = (1.8 km/min)(48 min) = 86.4 km, or about 54 miles.