Answer:
50%
Step-by-step explanation:
Let X = Green and red
Y = Red and blue
Z = Green and blue
( Buy green or red or blue )
⇒ (x + y) + (y + z) + (z + y) = 25 + 40 + 25
⇒ 2( x + y + z) = 100
∴ x + y + z = 50
Buy at least one shirt = 50%
So, did not buy any shirt = 100 - 50
= 50%