Help me with these 5 simple math problems.?

Question

1. 1/7 y = 9

y = ?

2. During a marathon, Elen was the winner in the womens wheelchair division, with a finishing time of 7.5262 hrs.. Round this time to the nearest hundreth of an hour.

3. 2 2/3 x 1 3/4

4. 10 5/12 - 20 5/18

5. Evaluate the expression for y= -0.8 and z= 7.16

z / y =

It's been a while for me and i forgot..lol...plz help solve so that i can understand better

Answer 1

1. 1/7 y = 9.  Multiply both sides of the equation by 7 to get y by itself:

y = 9 * 7 = 63

2. The hundredth place is the second digit after the decimal.  So, 7.5262 is rounded to 7.53.

3. Convert the mixed fractions into improper fractions:

2 2/3 = 8/3

1 3/4 = 7/4

(8/3) * (7/4) = 14/3

4. Again, change the mixed fractions into improper fractions:

10 5/12 = 125/12

20 5/8 = 365/18

Then to subtract, the denominators of both fractions must be the same:

The least common multiple of 12 & 18 is 36.

125/12 = 375/36

365/18 = 730/36

(375/36) - (730/36) = -355/36

5. 7.16 / -0.8 = -8.95

Answer 2

1.  y = 63

2.  7.53 hrs.

3.  4 8/12  or in lowest term 4 2/3

4.  1 14/36 or in lowest term 1 7/18

5.  20/179

Answer 3

1st:

1/7y = 9

y = 9(7/1)

y = 63

2nd:

= 7.5262

= 7.53

3rd:

= 2 2/3 * 1 3/4

= 8/3 * 7/4

= 56/12 or 14/3

= 4 2/3

4th:

= 10 5/12 - 20 5/18

= 125/12 - 365/18

= 375/36 - 730/36

= - 355/36

= - 9 31/36

5th:

= z/y

= 7.16/- 0.8

= - 8.95

Answer 4

For 1: divide 9 by 1/7. When you divide by a fraction, flip the fraction. So y = 9 * 7

Answer 5

1)

multiply both sides by 7

y = 63

2)

7.53

3)

8/3 X 7/4 = 56/12 = 4 2/3

Answer 6

I agree with the other person..

These are basic so if you are having trouble please see a teacher, your parents, or a tutor.  I don't want you to flip burgers when you are 30.  I am worried about your future and only you can do something to ensure that it is a good one.  Please find a study partner...

Answer 7

I was preparing for my GMAT some years ago and I felt kinda rusty with all these allegedly simple math problems :), so I can quite understand where you are coming from.

Here are the solutions:

1. 1/7y = 9

----> multiplying by 7 on both sides

7 x 1/7y = 9 x 7

Thus,

y = 63

2. Round of 7.5262 to the nearest hundredth of an hour.

---->this is how the decimal plane works :

hundreds tens units (decimal) tenths hundredths

---->so as the thousandths place is greater than 5, while rounding off the hundredths digit would be increased by 1.

Thus, 7.53 hrs

3. 2  2/3 x 1  3/4

These are two mixed fractions.

----> A mixed fraction is just a whole number and a fraction put together.

Step 1: Conver the mixed fraction into an improper fraction

    *  Multiply the whole number part by the fraction's denominator.

    * Add that to the numerator

    * Then write the result on top of the denominator.

By this conversion:

2 2/3 = (2x3 + 2)/3 = 8/3

1 3/4 = (1X4 + 3)/4 = 7/4

Step 2: Multiply these two fractions by multiplying the numerators together  to obtain a new numerator and multiplying the denominators together for the new denominator

Hence,

8/3 x 7/4 = (8x7)/(3x4)

              = 56/12

Step 3: Reduce the fraction (can be done in step 2 itself actually)

56/12 = 14/3

4. 10  5/12 -  20  5/18

Use Step 1 in soln 3 to convert mixed fractions into improper fractions

Thus,

125/12 - 365/18

Step 2: To add or subtract fractions: you need to identify the Least Common Multiple of the denominators.

Now to tell u how to calculate LCM of numbers... (long breath)

1. Place the numbers side by side ... 12 , 18

2. Divide by the smallest prime number either of these (or both) can be divided by, in this case 2. ...... 2 | 12 , 18

3. Write down the quotient of the resultant divisions under each number ....   2 | 12, 18

                        6,  9

4. Repeat step 2 and 3 over and over...till u are only left with 1s

................   2 | 12, 18

                   2 |   6,  9

                   3 |    3. 9

                   3 |    1, 3

                   3 |    1, 1

5. Multiply these primes together to get the LCM

(2 x 2 x 3 x 3 x 3) = 108

Step 3: To subtract fractions, divide the LCM by the denominator  of fraction A and multiple the result by the numerator of fraction A and subtract it from the same operation performed on fraction B.

{ (108/12)x10 - (108/18)x20 } / 108

Step 4:  (90 - 120) / 108 = -30/108

Step 5: Reduce the fraction is it -5/18 .. check it.

5. z / y = 7.16 / -0.8

+ divided by - is always - so.. keep this rule in mind and ignore the sign for now

Step 1. convert the decimals numbers into more manageable fractions like : 7.16 = 716 / 100 and 0.8 = 8/10

Step 2: z/y would then be (716 / 100 )x(10/8)

Step 3: should be easy going form here....

Step 4.. dont forget to add the minus sign as we had discussed earlier.

PHEW... hope that works. if i've made any mistakes (quite likely.. as i wrote the entire thing down in 5 mins... do let me know what the mistake was.

Answer 8

You should see a tutor.  I'm afraid that any answers provided through this interface will not help you fully comprehend the material