The cost of the two plans is same after 6 GB of data use.
Both the plan cost the same for 6 GB of data use. So, you can use any one of the two data plans.
Plan B is cheaper in the long run.
A) Carrier A
For [tex]3[/tex] GB, cost [tex]=[/tex] $[tex]35[/tex]
For [tex]4[/tex] GB, cost [tex]=[/tex] $[tex]35+[/tex]$[tex]8=[/tex]$[tex]43[/tex]
For [tex]5[/tex] GB, cost [tex]=[/tex] $[tex]43+[/tex]$[tex]8=[/tex]$[tex]51[/tex]
For [tex]6[/tex] GB, cost [tex]=[/tex] $[tex]51+[/tex]$[tex]8=[/tex]$[tex]59[/tex]
For [tex]7[/tex] GB, cost [tex]=[/tex] $[tex]59+[/tex]$[tex]8=[/tex]$[tex]67[/tex]
For [tex]8[/tex] GB, cost [tex]=[/tex] $[tex]67+[/tex]$[tex]8=[/tex]$[tex]75[/tex]
Carrier B
For [tex]5[/tex] GB, cost [tex]=[/tex] $[tex]55[/tex]
For [tex]6[/tex] GB, cost [tex]=[/tex] $[tex]55+[/tex]$[tex]4=[/tex]$[tex]59[/tex]
For [tex]7[/tex] GB, cost [tex]=[/tex] $[tex]59+[/tex]$[tex]4=[/tex]$[tex]63[/tex]
For [tex]8[/tex] GB, cost [tex]=[/tex] $[tex]63+[/tex]$[tex]4=[/tex]$[tex]67[/tex]
So, the cost of the two plans is same after [tex]6[/tex] GB of data use.
B) Here, both the plan cost the same for 6 GB of data use. So, you can use any one of the two data plans.
C) Clearly plan B is cheaper in the long run.
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