Question

Mr. Alvarado needs 15 1/8 pounds of chicken feed to fill his feeder. He has one bag of chicken feed that weighs 3 1/2 pounds and another bag of chicken feed that weighs 2 3/4 pounds. How many more pounds of chicken feed does Mr. Alvarado need to fill the chicken feeder?

A: 9 1/8 Lbs

B: 8 7/8 Lbs

C: 9 7/8 Lbs

D: 6 1/4 Lbs

Answer 1

B: 8 7/8 Lbs

Explanation:

answer =
`15(1)/(8) -3(1)/(2) -2(3)/(4)`

step 1 find a common denominator

common denominator - 8

* apply *

`(1^*^1)/(8^*^8) =(1)/(8) \\\\(1^*^4)/(2^*^4) =(4)/(8) \\\\(3^*^2)/(4^*^2) =(6)/(8)`

now we have

`15(1)/(8) -3(4)/(8) -2(6)/(8)`

step 2 make each fraction a improper fraction

We can do this my multiplying the big number by the denominator and adding that to the numerator.

`15*8=120\\120+1=121\\(121)/(8) \\\\3*8=24\\24+4=28\\(28)/(8) \\\\2*8=16\\16+6=22\\(22)/(8)`

now we have

`(121)/(8) -(28)/(8) -(22)/(8)`

Now we can subtract

remember when subtracting fractions you only subtract the numerators. ( so we keep the denominator as 8 )

so 121 - 28 - 22 = 71

so the answer is
`(71)/(8)`

finally we want to change the answer back into a mixed fraction

To do this we divided 71 and 8

8 can go into 71 8 times

8 * 8 = 64

71 - 64 = 7

We're left with
`8(7)/(8)`