Bunuel wrote:

In the last month Super Tele-Com has offered flat-rate service packages on landline telephones, cellular phones and DSL high speed internet to a select group of long-time customers in a particular city. Of this group thirty percent opted to sign up for only one of the three flat-rate packages. While no customers opted to just take flat-rate cell phone and DSL service, 65 people decided to sign up for only flat-rate land line service and one other flat-rate service. If 330 people signed up for some form of flat-rate service, how many people opted to sign up for all three packages?

A. 166

B. 140

C. 98

D. 77

E. 65

We can create the following equation:

# of people who signed up = # signed up for 1 package + # signed up for 2 packages + # signed up for 3 packages + # signed up for 0 packages

Since 30 percent of the 330 people signed up for only one package, we can say:

# signed up for 1 package = 0.3 x 330 = 99

Since no customers opted to just take flat-rate cell phone and DSL service and 65 people decided to sign up for only flat-rate landline service and one other flat-rate service, we can say:

# signed up for 2 packages = 65

Since all 330 people signed up for some form of flat-rate service, we can say:

# signed up for 0 packages = 0

Finally we can let T = # signed up for 3 packages and create the following equation to determine T:

330 = 0.3(330) + 65 + T + 0

330 = 99 + 65 + T

330 = 164 + T

166 = T

Answer: A

_________________

Scott Woodbury-Stewart

Founder and CEO

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