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qwelly [4]
2 years ago
13

How would you find x?

Mathematics
1 answer:
Vanyuwa [196]2 years ago
8 0

Answer:

A

Step-by-step explanation:

x=7

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A lab technician needs 60mL of 25% acid solution for a certain experiment , but he has only 10% solution and 40% solution. How m
V125BC [204]

Answer:

  • 10%: 30 mL
  • 40%: 30 mL

Step-by-step explanation:

The needed concentration is exactly halfway between the available concentrations, hence they must be mixed equally.

He should mix 30 mL each of the 10% and 40% solutions.

_____

The first step in solving any problem is to look at the given information, and at what is being asked for. Here, the mix that is being asked for is exactly halfway between the given concentrations, so you know without any further contemplation that the mix will be 50%/50% of each.

__

If the mix were something else, there are several ways the problem can be solved. I like to use a diagram that puts the available concentrations on the left in a column with the highest on top, the needed concentration in the next column in the middle, and the differences of these numbers on the diagonals in the right column.

<u>Example</u>: if the needed mix is 15%, the diagram would look like ...

   40            5

          15

   10           25

The numbers on the right tell you the proportions required (5:25 = 1:5). For this example, you need 1 part 40% solution and 5 parts 10% solution to make a mix that is 15%. That's a total of 6 parts, so each "part" is 10 mL for 60 mL of solution.

We chose this example so every number in the diagram is different, so you could see how the instructions for use apply.

__

Another way to solve this is to let a variable represent the amount needed of <em>the highest concentration</em>. If we let that variable be x, for the given problem, we can write the equation for the amount of acid in the mix as ...

  40%(x) + 10%(60 -x) = 25%(60)

  0.30x = 9 . . . . . . . . subtract 6, simplify

  x = 9/0.30 = 30 . . . . . mL of 40% solution

6 0
3 years ago
HELP ASAP!!! QUESTION IN PHOTO! MARKING BRAINLIEST
Norma-Jean [14]
What the question on
3 0
2 years ago
from 2002 to 2012, the number of a particular make of cars sold at a dealership yearly declined to 500. The number is expected t
Alinara [238K]
To determine the number of cars that will be sold by the year 2020, we will use the equation,

     N = (N1)(1 - r)^(t)

where N1 is the starting number of cars, r is the rate of the decrease, and t is the number of years from 2012. Substituting the konwn values,

   N = (500)(1 - 0.028)^(8)
    N = 398.38

The closest integer to the calculated value is 398. Thus, the answer is 398 cars. 
3 0
3 years ago
Which point is a solution to y&lt;4x+5?
rusak2 [61]

The answer is C because -2 is less than or equal to 5. (4 times 0 is 0)

5 0
3 years ago
Read 2 more answers
Find the volume of a cylinder. Round your answer to the nearest tenth. Do not add a comma.
natali 33 [55]

Answer:

Step-by-step explanation:

Base -- find the radius

radius -- 67.8 (135.6^2 /2)

h=11.2

Volume = 2385.59

2385.60

5 0
3 years ago
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