20r + 11r + –19r − –4 = –20

r = -2

Step-by-step explanation:

20r + 11r - 19r + 4 = -20

12r + 4 = -20

subtract 4 from both sides of the equation

12r + 4 - 4 = -20 - 4

12r = -24

divide both sides by 12

12r/12 = -24/12

r = -2

you didn't give me the choices, so i will just give you the graph so you can look at your choices and choose the right one.

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