Quantitative Reasoning Questions...Someone help!!!

[etoolky1]

Today, I went through the practice test from the ADA book. I can't figure out some of the questions. I didn't think I was that bad at math but my test is in 2 weeks and I need help....!!!!!!!

1. 10 is to 2y as 25x is to which of the following:
a. 5x
b.5xy
c.5x/y
d.x/5y
e.5y/x

2. if 3 liters of 40% orange juice and 1 liter of 50% orange juice are mixed, which of the following is the percentage of orange juice in the mixture?
a. 90
b. 85
c. 47.5
d. 45
e.42.5

3. How do you average course grades such as a question with: the final exam is one third of the average & preliminary grades 2/3...

4. A mothers age is three times her daughters age. In twelve years the mother's age will be twice the daughters age at that time. How old is the mother now?
a.18
b.20
c.24
d.30
e.36

5. If y=x+2/x-3 then which of the following represents x?
a.(3y+2)/(y-1)
b.(3y+2)/👍
c.(3y-2)/(y+1)
d.(5y)/(y+1)
e.(3y-2)/(y-1)

6. formula for variance????

7. Jill has 6 different books. In how many ways can jill select six different books?

The ADA practice test does not give explanations so I thought maybe someone could expalin how you work these problems. I guess my math is rusty bc. these all seem like simple problems but I can't remember!!

Thanks for any help..

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[Mr.E]

Today, I went through the practice test from the ADA book. I can't figure out some of the questions. I didn't think I was that bad at math but my test is in 2 weeks and I need help....!!!!!!!

1. 10 is to 2y as 25x is to which of the following:
a. 5x
b.5xy
c.5x/y
d.x/5y
e.5y/x

2. if 3 liters of 40% orange juice and 1 liter of 50% orange juice are mixed, which of the following is the percentage of orange juice in the mixture?
a. 90
b. 85
c. 47.5
d. 45
e.42.5

3. How do you average course grades such as a question with: the final exam is one third of the average & preliminary grades 2/3...

4. A mothers age is three times her daughters age. In twelve years the mother's age will be twice the daughters age at that time. How old is the mother now?
a.18
b.20
c.24
d.30
e.36

5. If y=x+2/x-3 then which of the following represents x?
a.(3y+2)/(y-1)
b.(3y+2)/👍
c.(3y-2)/(y+1)
d.(5y)/(y+1)
e.(3y-2)/(y-1)

6. formula for variance????

7. Jill has 6 different books. In how many ways can jill select six different books?

The ADA practice test does not give explanations so I thought maybe someone could expalin how you work these problems. I guess my math is rusty bc. these all seem like simple problems but I can't remember!!

Thanks for any help..

For the first problem set up the equation like a ratio.

10/2y = 25x/y, then solve for y. You will end up with 5xy.


For the third problem set up the equation as follows:
Mother's age = 3daughter's age (or 3d)
Daughter's age = d

Twelve years later:

Mother's age = M+12
Daughter's age d+12

The problem says that the mother will be twice the daughters age of her daughter after twelve years, so this should look like this:

2(d+12)

Set up the equation as follows:

M+12 = 2(d+12)

Next, substitute for M the first variable (i.e. 3d)

The equation will look like this:
3d+12 = 2(d+12). Next, solve for d and then substitue the answer you got for d for the mother's age (like this: 2d = 3(12)= 36

The last problem is a permutation problem.

Try doing it like this:

(6*5*4*3*2*1)!/(4*3*2*1)! = 30 The numerator represent the total number of items. The denominator reprsents the amount of items being selected. In this case, Jill selects 2 books from 6, so the denominator is 6-2 =4!

As for the other problems I'm not sure how to do them. Hope this helps and good luck with the test in two weeks.

 

[Mr.E]

Here is how you do the percentage problem with orange juice. I think it is problem 14 in the ADA manual.

Take 3(.4)+1(.5)=1.7
Then divide answer by 4 and multiply by 100 to get percentage.

Answer: E

 

[Gasedo]

Today, I went through the practice test from the ADA book. I can't figure out some of the questions. I didn't think I was that bad at math but my test is in 2 weeks and I need help....!!!!!!!

1. 10 is to 2y as 25x is to which of the following:
a. 5x
b.5xy
c.5x/y
d.x/5y
e.5y/x

2. if 3 liters of 40% orange juice and 1 liter of 50% orange juice are mixed, which of the following is the percentage of orange juice in the mixture?
a. 90
b. 85
c. 47.5
d. 45
e.42.5

3. How do you average course grades such as a question with: the final exam is one third of the average & preliminary grades 2/3...

4. A mothers age is three times her daughters age. In twelve years the mother's age will be twice the daughters age at that time. How old is the mother now?
a.18
b.20
c.24
d.30
e.36

5. If y=x+2/x-3 then which of the following represents x?
a.(3y+2)/(y-1)
b.(3y+2)/👍
c.(3y-2)/(y+1)
d.(5y)/(y+1)
e.(3y-2)/(y-1)

6. formula for variance????

7. Jill has 6 different books. In how many ways can jill select six different books?

The ADA practice test does not give explanations so I thought maybe someone could expalin how you work these problems. I guess my math is rusty bc. these all seem like simple problems but I can't remember!!

Thanks for any help..

For question 2:
First find how much is 3 L from 40%:
3L*40/100 = 1.2L

Then find how much is 1L from 50%
1L*50/100 = 0.5L

Then you add the results and divide by the total *100 to find out the percentage of orange juice in the mixture:

1.2L+0.5L = 1.7L
1.7L/4L *100 = 42.5L
So the answer is e.

For question 5:
Y=(x+2)/(x-3) Now solve for x

Y(x-3) = (x+2)
Xy-3y = (x+2)
Xy-x = 2+3y
X(y-1) = 2+3y
X = (2+3Y)/(y-1)
OR
X = (3y+2)/(y-1)

For question 6:
For example, if you have 4 numbers: 1,2,3,4
Mean = 1+2+3+4 = 10
Variance = [(1+10)^2 + (2+10)^2 + (3+10)^2 + (4+10)^2] / (4-1)