Answer: For the sum of 130
First: $90
Second: $40
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=130 since their sum is 130.
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=130, rearrange to b=130-a and substitute into 15a+5b=1550.
15a + 5 (130-a)=1550
15a+650-5a=1550
10a+650-650=1550-650
10a=900
a=$90 was charged by the first mechanic.
We substitute to find the second mechanic's rate.
90+b=130
90-90+b=130-90
b= $40 was charged by the second mechanic
The probability that he would have done at least this well if he had no ESP is 0.99979
<h3>What is the probability of determining that he would have done well with no ESP?</h3>
To determine the probability, we need to first find the probability of doing well with ESP.
The probability of having 20 correct answers out of 23 coin flips is:
Since we have 20 correct answers, we also need to find the probability of getting 3 answers wrong, which is:
There are 
= 1771 ways to get 20 correct answers out of 23.
Therefore, the probability of doing well with ESP is:
= 0.00021
The probability that he would have at least done well if he had no ESP is:
= 1 - 0.00021
= 0.99979
Learn more about probability here:
brainly.com/question/24756209
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It would be C!!!!!!!!!!!!!!!
Answer:
you should know this. you tell me how many?
Which number is the under lined digit?
