You are buying decorations for a birthday party. Six rolls of crepe paper and 20 balloons cost $11.90. After you start decorating, you need more supplies. You buy 2 more rolls of crepe paper and 15 more balloons for $6.05.

$1.15

Step-by-step explanation:

The question is How much did each roll of crepe paper cost?

Let the cost of crepe paper be x

Let the cost of balloons be y.

Six rolls of crepe paper and 20 balloons cost $11.90. This will be:

6x + 20y = 11.90 i

2 more rolls of crepe paper and 15 more balloons for $6.05. This will be:

2x + 15y = 6.05 ii

6x + 20y = 11.90 i

2x + 15y = 6.05 ii

Multiply equation i by 15

Multiply equation ii by 20

90x + 300y = 178.50 iii

40x + 300y = 121 iv

Subtract iv from iii

50x = 57.50

x = 57.50/50

x = 1.15

Therefore, a crepe paper cost $1.15

step-by-step explanation:

i found the life tables for the year 2012. 

life table of males at age 30. probability of dying between ages x and x+1

total population:  

29–30 . . . . . . . . . . . . 0.001030

30–31 . . . . . . . . . . . . 0.001061

males:  

29–30 . . . . . . . . . . . . 0.001420

30–31 . . . . . . . . . . . . 0.001448

white population

29–30 . . . . . . . . . . . . 0.001005

30–31 . . . . . . . . . . . . 0.001037

white males

29–30 . . . . . . . . . . . . 0.001372

30–31 . . . . . . . . . . . . 0.001399

non hispanic white population

29–30 . . . . . . . . . . . . 0.001083

30–31 . . . . . . . . . . . . 0.001116

non hispanic white males

29–30 . . . . . . . . . . . . 0.001477

30–31 . . . . . . . . . . . . 0.001503

jacob, non hispanic white male. 30 years old.

probability that jacob lives to be 30 years old. 

since the given probabilities are probabilities of dying, i think we simply subtract it from 1 to get the probability of living. we will use the probability of non hispanic white male.

                                          probability of living to be 30 y.o.

29 - 30 : 1 - 0.001477 = 0.998523

30 - 31 : 1 - 0.001503 = 0.998497