Answer:
Step-by-step explanation:
a + 9 = 15
a = 15 - 9
a = 6
c + 9 = 16
c = 16 - 9
c = 7
d = c + 9
= 7 + 9
= 16
e = d + 15
= 16 + 15
e = 31
P(selecting a boy) = total boy /total pupils = 16/31
