In
a certain school, 140 students take either Chemistry or physics. 160 take
chemistry and 100 take both subjects. Find those who take physics.
Solution
In
most cases, OR stands for union whereas AND/BOTH, stands for intersection.
Let
Chemistry = n(C), physics = n(P).
n(C)=
160 ,
n(P)=
?
n(CuP)
= 140,
n(CnP)=
100
n(CuP)
= n(C) + n(P) - n(CnP)
140
= 160 + n(P) – 100
140
= 160 – 100 + n(P)
140
= 60+ n(P)
140
- 60 = n(P)
n(P)=
80
Hence those taking physics are 80.
TRY THIS………….
In
a certain school, 185 students take either Chemistry or French. 160 take
chemistry and 130 take both subjects. Find those who take French.
No comments:
Post a Comment