Okay so you have to add up 15 and 11 and 4 so your answer is y=30
        
             
        
        
        
Answer:
17/20.........................
 
        
             
        
        
        
2.25 for the first mile. That leaves 4.2 miles. 
4 * 0.1 = 0.4
0.15 * 4 = $6.00 
0.15 * 2 = 0.3
$6.30 + $2.25 = $8.55
$10.00 - $8.55 = $1.45
The driver's tip was $1.45.