Polly is comparing the cost of cell phone services. The phone she wants costs $899 at BT&T Cellular, and the unlimited calling plan through their carrier would cost $2 per day. At Revizon Electronics, Polly could purchase the same phone for $799 and also get an unlimited calling plan for $3 per day. After some number of days, the two options would end up having the same total cost. What would the total cost be? How long would that take?

The total cost = $1,099

It would take 100 days

Step-by-step explanation:

Let

x = number of days

Cost of BT&T Cellular = 899 + 2x

Cost of Revizon Electronics = 799 + 3x

Equate the cost of both cell phone services.

899 + 2x = 799 + 3x

899 - 799 = 3x - 2x

100 = x

x = number of days = 100 days

Cost of BT&T Cellular = 899 + 2x

= 899 + 2(100)

= 899 + 200

= $1,099

Cost of Revizon Electronics = 799 + 3x

= 799 + 3(100)

= 799 + 300

= $1,099

option 1 is correct.

step-by-step explanation:

y varies inversely with x and constant of variation is 4

the equation will be:

y = k/x

where k =4 so,

y = 4/x

if we put values of x of option 1 in the above equation and find values of y

y = 4/-2 => y =-2

y = 4/-1 => y = -4

y = 4/1 => y = 4

y = 4/2 => y =2

so, all the values of x and y are correct.

if we put values of x given in other options and find value of y we cannot find whole table satisfying the equation.

hence option 1 is correct.

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560