1/10 of 1,700,000 km² is 170,000 km² .
Answer: m=-1, b=-2
Step-by-step explanation:
Answer: C.-1.5
Step-by-step explanation:
Given: The burning time of a very large candle is normally distributed with mean
of 2500 hours and standard deviation
of 20 hours.
Let X be a random variable that represent the burning time of a very large candle.
Formula: 
For X = 2470
So, the z-score they corresponds to a lifespan of 2470 hours. =-1.5
Hence, the correct option is C.-1.5.
The present age of mother and her daughter respectively are; 40 and 10 years respectively.
<h3>How to Solve Algebra Word Problems?</h3>
Let x and y be the present age of mother and her daughter respectively.
Therefore;
x + y = 50
x = 50 − y .....(1)
After 20 years, mother's age will be twice her daughter's age at the time. Thus;
x + 20 = 2(y + 20)
x − 2y = 20 .....(2)
Plugging eq 1 into eq 2 gives us;
50 − y − 2y = 20
3y = 30
y = 10
Thus;
x = 50 − 10
x = 40
Thus, the present age of mother and her daughter is 40 and 10 years respectively.
Translation of the question into English is;
The sum of the present ages of mother and her daughter is 50 years. After 20 years, mother's age will be twice her daughter's age at the time. Find their present ages.
Read more about Algebra Word Problems at; brainly.com/question/21405634
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So if 6 out of 40 are incorrect, 40-6= 36 must be correct.
In order to gain percentage you do proportions.
36/40 = x/100.
Multiply 36 times 100 then divide by 40, which is 90.
The answer is 90%.
90% of the questions he got were correct.
