68 miles to 42.5 is what percent of decrease??

1 answer:

6 0

68 miles to 42.5's percent of decrease is: 37.5%
Using proportions. 68 miles - 42.5 = 25.5

25.5 x
------ = -----
68 100

Cross multiply:
25.5 x 100 = 2550
68 multiply x = 68x
2550 divided by 68 = 37.5
x = 37.5%

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serg [7]

Solving a system of equations we will see that we need to use 40 liters of the 80% acid solution, and the other 20 liters are of the 35% acid solution.

<h3>How many liters of each solution do we need to use?</h3>

First, we need to define the variables:

x = liters of the 35% acid used.
y = liters of the 80% acid used.

We know that we want to produce 60 liters of 65% acid, then we have the system of equations:

x + y = 60

x*0.35 + y*0.80 = 60*0.65

(in the second equation we wrote the percentages in decimal form).

To solve this we need to isolate one of the variables in one equation and then replace it in other one, isolating x we get:

x = 60 - y

Replacing that in the other equation:

(60 - y)*0.35 + y*0.80 = 60*0.65

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y*0.45 = 60*0.30

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If you want to learn more about systems of equations:

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7 0

2 years ago

In order to receive a b in your english class, you must earn more than 350 points of reading credits. last week you earned 120 p

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120 + 90 = 210 points
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3 years ago

Please help

ASHA 777 [7]

Answer:

(-6,4)

Step-by-step explanation:

The equations are:

$x^2+4y^2=100\\4y-x^2=-20$