85 vehicles with a total of 188 wheels registered for a bike/trike race. How many vehicles and how many tricycles were at the race?

X = number of bicycles y = number of tricycles

x + y = 85 (1)

2x + 3y = 188 (2)

(1) * - 2 = (3) - 2x - 2y = - 170 (3)

(2) + (3) = (4) y = 18 (4)

substitute y into 1st equation (1)

x + 18 = 85

x = 67

67 bikes, 18 tricycles