Answer:
15
Step-by-step explanation:
Finding total number of pupils(y)
3/y x 360°=27°
3x360°/y=27°
1080°/y=27°
1080°=27°y
1080°/27°=27°y/27°
40=y
Number of pupils who said that Maths was their favorite (z)
z/40x360°=135°
360°z/40=135°
360°z=135°x40
360°z=5400°
360°z/360°=5400°/360°
z=15
