(3a x3 -5bx3) + -------ax3 + -----------bx3 = (ax3 + bx3).
2 answers:
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Answer:
Step-by-step explanation:
Let n(U) be total amount or customers = 100%
n(C) = 80% of its customers subscribe to its cable TV service.
n(I) = 41% of its customers subscribe to its Internet service.
n(T) = 31% of its customers subscribe to its telephone service.
n(CnI) = 25% of its customers subscribe to both its cable TV and Internet service.
n(CnT) = 20% of its customers subscribe to both its cable TV and phone service.
n(InT) = 22% of its customers subscribe to both its Internet and phone service.
n(CnInT) = 15% of its customers subscribe to all three services
number of those that subscribed to TV only = n(C) - (n(CnInT')+(n(CnI'nT)+(n(CnInT))
= 80-[(25-15)+(20-15)+15]
= 80-{10+5+15)
= 80-30
= 50
Hence 50% read cable TV only
Pr(cable TV only) = 50/100 = 1/2
2) number of people that read internet and cable TV = 25%
Pr(internet and cable) = 25/100 = 1/4
3) number of people that had exactly two services are;
n(cable and internet only)+n(internet and phone only)+(cable and phone only)
= (25-15)+(22-15)+(20-15)
= 10+7+4
= 21%
Hence 21℅ read exactly two services
pr(exactly 2 services) = 21/100
4) number of people that read internet and cable only = n(CnI) - n(CnInP)
= 25-15 = 10%
Pr(Internet and cable only) = 10/100 = 1/10
