$2.50 was left for each person.
4(9.50) + x = 48
38 + x = 48
subtract 38 on both sides
x = 10
10$ was left in total by all 4 people
10/4 = 2.50
$2.50 was left over for each person
 
        
             
        
        
        
Answer:
Luis
Step-by-step explanation:
One hour is 60 minutes total, leaving and extra 30 minutes for Ava, which is half of 60. So, in fraction form, she walked 1 1/2 OR 1 2/4 hours, which is less than Luis. He walked about an hour and 45 minutes total, or 105 minutes.
 
        
             
        
        
        
After understanding the problem, formulate equations to determine the unknown. Let x be the price of one book. Equating Alana&Petra's expense with Angus' would be
5x + 4x +5 = 19x - 10
The 5 in the left side is needed because Angus' expense is $5 more. Also, the 10 on the right side represents the $10 discount. Solving the equation,
19x = 9x = 5+10
10x = 15
x = $1.5
Therefore, the book costs $1.5. 
        
             
        
        
        
Mean or Average is all of the sums divided by how many of the choices are there, so all of 10,126+9,99+12,398+12,007+4567=49097 and divided by all the choices you have which is 5 is 9819.4