Question 1203110
<font color=black size=3>
c = number of cars
v = number of vans


c+v = total number of vehicles
c+v = 61


4c = amount of money from the cars only ($4 each)
6v = amount of money from the vans only ($6 each)
4c+6v = total amount of money raised
4c+6v = 278



The system of equations is
c+v = 61
4c+6v = 278


I'll use substitution to solve.
Isolate c in the 1st equation
c+v = 61
c = 61-v


Plug that into the other equation to isolate v.
4c+6v = 278
4(61-v)+6v = 278
244-4v+6v = 278
244+2v = 278
2v = 278-244
2v = 34
v = 34/2
v = 17


Use this to determine c.
c = 61-v
c = 61-17
c = 44




Answers:
Number of cars = <font size=4 color=red>44</font> 
Number of vans = <font size=4 color=red>17</font> 
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