Ed counts 23 black cars, 9 red cars, 17 blue cars, 25 white cars, and 21 silver cars during 20 minutes of watching. How many more white and blue cars are there than silver and red cars

Answer 1

w + b = 25 + 17 = 42

s + r = 21 + 9 = 30

42 - 30 = 12 more