Answer:
Check the explanation
Step-by-step explanation:
From the given differences of SAT scores
find the mean and standard deviation of difference.
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Let x and y be the rate per hour for Mechanic 1 and 2 respectively.
Then,
x+y=205 ---------- (1)
Additionally,
10x+15y = 2500 ------ (2)
Solving equations 1 and 2;
Multiply (1) by 10 and subtract two from the result,
10x+10y = 2050
10x +15 y =2500
----------------------
-5 y = --450 => y = 450/5 = $90
Then,
x= 205-90 = $115
Therefore,
Mechanic 1 charged $115 per hour
Mechanic 2 charged $90 per hour
Answer:
D is the correct answer
Step-by-step explanation:
I just took the test