Kirsten has 25 coins. in her collection she has dimes and quarters. if the total is $4.00. how many dimes and how many quarters does she have? part a: write a system of equations to express this situation. let d= the number of dimes and q= the number of quarters. part b: solve the system of equations to determine the dimes and number of quarters

Step-by-step explanation:

Because we have 2 unknowns, we need 2 equations.  One equation will represent the number of coins we have, the other will represent the value of the coins, since they are definitely not the same.  If we have a total of 25 coins made up of dimes and quarters:

d + q = 25

Now for the value of these, we know that a dime is worth .10 and a quarter is worth .25, and we also know that the total value of the coins we have is $4.  

.10d + .25q = 4

There are the 2 equations we need.  Go back to the first one and solve it for either d or q.  Let's solve for d:

d = 25 - q

Now use the substitution method and sub in 25 - q for d in the other equation:

.10(25 - q) + .25q = 4 and

2.5 - .10q + .25q = 4 and

2.5 + .15q = 4 and

.15q = 1.5 so

q = 10

That means we have 10 quarters.  Sub that in for q in the first equation to solve for d:

d + q = 25 and

d + 10 = 25 so

d = 15

We have 15 dimes and 10 quarters.

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

1/6

step-by-step explanation: