Length is the up and down while area is the inside
I believe the first answer is correct
a quarter is 1.75 mm thick
1 mm = 0.0393701 inches
0.0393701/12 = 25.4 mm per inch
25.4/1.75 = 14.5 quarters per inch
14.5 x 12 = 174 quarters per foot
174 x 0.25 = 43.50
$43.50 for a foot of quarters

Explanation:
Since we have given that
Speed at which Eugene walked all the way to school = 3 mph
After realizing that she forgot her math book, she ran back
Speed at which Eugene walked back to her house = 7 mph
Let the distance between her house and her school be x
According to question,

Hence,

3x-6≤9
3x≤15
x≤5
so the answer is x≤5