Let x be the number of ordinary cars
Let y be the number of SUV's
The difference between the number of ordinary cars and the number of suvs is 17.
So x-y=17 ----> first equation
The number of ordinary cars is larger than the number of sport utility vehicles by 77.3%.
ordinary cars = SUV + 77.3% of SUV
x = y + 0.773y
x = 1.773y
Now we solve for y
We plug in x=1.773y in first equation
1.773y - y=17
0.773y = 17
y = 21.9922
Number of SUV's = 22