Say you are at a bike shop. They sell tricycles, bicycles and unicycles. If there is a total of 150 wheels and 70 seats. If there are twice as many bicycles as tricycles how many of each type of bike do you have?

Answer 1

T + B + U = 70

B = 2T

U + 2B + 3T = 150
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Solve those equations simultaneously.

2T + B = 80
2B = 80
B = 40
T = B/2 = 20
U = 70 - 40 - 20 = 10