A ratio of white to black cars is 2:7 A ratio of white to red cars is 3:11. There is a total of 343 white red and black cars. How many black cars are there?
B==Black, W==White, R==Red
W / B ==2 / 7..........................................(1)
W / R ==3 / 11........................................(2)
B + W + R ==343....................................(3), solve for B, W, R
Use substitution to get:
B ==147 - Number of black cars
W==42 - Number of white cars
R ==154 - Number of red cars
