Are you supposed to find B?
I think the percent change would be 25%
Answer:
Price of each phone: 
Price of each accessory: 
Step-by-step explanation:
Let be "p" the price in dollars of each phone and "a" the price in dollars of each accessory.
Set up a system of equations:

You can use the Elimination Method to solve the system.
Multiply the second equation by -2 and add both equations:

Substitute the value of "a" into the first equation and solve for "p":

Let mass of truck be t
mass of car A be a
and carB be b
so , a=2b-5
t=a+2135
putting a into t...
t=2b-5+2135
so, a+b+t=11350 ( putting all values)
2b-5+b+2b-5+2135=11350
so b=1845
a=3685
t=5820
so weight of Car A is 3685 lb
weight of Car B is 1845 lb
and truck is 5820 lb ......answers !!