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3 years ago

Two mechanics worked on a car. The first mechanic worked for 15

Mathematics

1 answer:

4vir4ik [10]3 years ago

4 0

Answer:

First: $65

Second: $115

Step-by-step explanation:

We write equations for each part of this situation.

<u>The Total Charge</u>

Together they charged 1550. This means 1550 is made up of the first mechanics rate for 15 hours and the second's rate for 5 hours. Lets call the first's rate a, so he charges 15a. The second's let's call b. He charges 5b. We add them together 15a+5b=1550.

<u>The Sum of the Rates</u>

Since the first's rate is a and the second is b, we can write a+b=180 since their sum is 180.

We solve for a and b by substituting one equation into another. Solve for the variable. Then substitute the value into the equation to find the other variable.

For a+b=180, rearrange to b=180-a and substitute into 15a+5b=1550.

15a + 5 (180-a)=1550

15a+900-5a=1550

10a+900-900=1550-900

10a=650

a=$65 was charged by the first mechanic.

We substitute to find the second mechanic's rate.

65+b=180

65-65+b=180-65

b= $115 was charged by the second mechanic

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5x+20y=4<br> x=-4y+1<br><br> Solve for x/y

Andrews [41]

Hi there!

Looks like a lot of work is going on here.

Let's start by solving this equation for the x.

$5x + 20y = 4$

Step 1) Add -20y to both sides.

$5x + 20y + - 20y = 4 - 20y 5x = -20y + 4$

Step 2) Divide both sides by 5.

$\frac{5x}{5} = \frac{-20y + 4}{5}$

$x = -4y + \frac{4}{5}$

Final Answer:

$x = -4y + \frac{4}{5}$

Now, let's solve for y.

Step 1) Add -5x to both sides.

$5x + 20y + - 5x = 4 + - 5x 20y = -5x + 4$

Step 2) Divide both sides by 20.

$\frac{20y}{20} = \frac{-5x + 4}{20}$

$y = \frac{-1}{4} x + \frac{1}{5}$

Final Answer:

$y = \frac{-1}{4} x + \frac{1}{5}$

Hope this helps! :D

Hint - When you have two variables in an equation, and you want to solve for one, the other will end up in your answer. :)

6 0

3 years ago

If you draw a card with a value of 4 or less from a standard deck of cards, I will pay you 165$ if not your pay me $45. (Aces ar

jekas [21]

Answer: The required expected value is $3.46.

Step-by-step explanation:

Since we have given that

Number of value of 4 or less are

2,3,4

So, there are 12 in numbers.

So, probability would be

$\dfrac{12}{52}$

Since Aces are considered as the highest card in the deck.

So, remaining probability would be

$\dfrac{40}{12}$

Amount paid or value of 4 or less = $165

Amount not paid for other case = $45

So, the expected value would be

$\dfrac{12}{52}\times 165-\dfrac{40}{52}\times 45\\\\=\dfrac{1980}{52}-\dfrac{1800}{52}\\\\=\dfrac{180}{52}\\\\=3.46$

Hence, the required expected value is $3.46.

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Todos los numeros naturales son enteros

Mamont248 [21]

Pee brain. . .you get it okay

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amid [387]

Answer:

x = 125

Step-by-step explanation:

Given

$\frac{x}{5}$ = 25

Multiply both sides by 5 to clear the fraction

x = 5 × 25 = 125

x = 125

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3 years ago

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