An art teacher has a box of pencils. 1/10 are green, 1/2 are blue, 1/4 are orange, and the remaining 45 are red. How many pencils are orange?

Answer 1

1/10 + 1/2 + 1/4 = 31/40
So,

9/40 x = 45
x = 200

So, 1/4 * 200 = 50 are orange