solve for x if 15/x = (8 / 1/35)

Question

i probably havnt written this correctly either but it is what is x if 15 over x = 8 over 1 and 3/5

Answer 1

The equation is tricky because of the mixed number in the denominator of one of the fractions, so it looks like a fraction within a fraction. But, all it needs is some rearranging.

 

You are solving for x in the problem 15/x= 8/(1 3/5). Because there is a mixed number, you can make it an improper fraction by having the whole number (1) be represented as a fraction [1=5/5 so 1 3/5= (5/5) + 3/5= 8/5)].

 

Because you now have 8/ (8/5), you must multiply by its reciprocal ("flip" the denominator and numerator) so now its 8•(5/8) which makes the 8's cancel. This leaves you with just 5 [8•(5/8)=(8/1)•5/8=5].

 

Now the equation is 15/x =5. Solve for x! You can do this by multiplying by x on both sides so x appears after the equal sign by cancelling it as a denominator [15/x •x=5•x which is 15=5x]. Dividing both sides by 5 to isolate the x, x is 3.

 

If you have time, check by plugging in "3" for x.  15/(3)=8/(8/5) which is 15/3=8•5/8 or 5=5. Does 5=5?

 

YES, so x is 3

 

 

Answer 2

Hi, Shannon,

 

You were pretty close. First convert the 1and 3/5 to 8/5. Then 8 over 8/5 is dividing by a fraction, so flip the bottom and it becomes 8*(5/8) = 5. Then 15/x = 5, multiply through by x, it becomes 15=5x, so x = 3. I can give you a lot more help if you would like some algebra tutoring.

Answer 3

1 and 3/5 as you would put is read as a mixed number.  Simply change the mixed number to an improper fraction.

 

1 3/5 = 8 / 5

 

 

Now the equation becomes

 

15 / x = 8 / (8 / 5)

 

15 / x = 8 * (5 / 8)

 

15 / x = 5

 

 

Multiply both sides of the equation by x.

 

15 = 5x

 

 

Divide both sides of the equation by 5.

 

x = 3