Answer
Step-by-step explanation:
Replace all occurrences of
+
−
with a single
−
. A plus sign followed by a minus sign has the same mathematical meaning as a single minus sign because
1
⋅
−
1
=
−
1
−
20
−
2
m
<span>B. 16 quarts of the 2% milk and 24 quarts of the 7% milk
First, let's create an equation to solve.
x = quarts of 2% milk
(40-x) = quarts of 7% milk
So we have the equation
x*2 + (40-x)*7 = 40*5
Now to solve for x
x*2 + (40-x)*7 = 40*5
x*2 + 7*40 - 7*x = 40*5
x*2 - 7*x = 40*5 - 7*40
-5*x = - 2*40
x = 2*8
x = 16
So we need 16 quarts of 2% milk and 40-16 = 24 quarts of 7%, which matches option "B".</span>
Mabel spends 4 hours editing a 3 minute video. she edits at a constant rate. how long does mabel spend to edit a 9 minute video?
she spends 4 hours on a 3 minute video
so there are 60 minutes in an hour
4 hours with 60 minutes- 4x60=240
so she spent 240 minutes on a 3 minute video
3 divided by 240
3/240= 0.0125
so her constant rate is 0.0125 minutes an hour
so divide 9 minutes by her constant rate
9/0.0125 = 720
so she spends 720 minutes on a 9 minute video.
divide 720 by 60 since there are 60 minutes in an hour
720/60 = 12
so she spends 12 hours on a 9minute video