A number is multiplied by 4 and then 12 is added. the result is 36. what is the number?
2 answers:
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Answer:
<h3><em>D. 880 = 45d + 70; 18 days.</em></h3>Step-by-step explanation:
We are given fixed monthly charge = $70.
The cost of preschool per day = $45.
Number of days = d.
Total cost of d days = cost per day × number of days + fixed monthly charge.
Therefore, we get equation
880 = 45×d+70
<h3>880 = 45d +70.</h3>Now, we need to solve the equation for d.
Subtracting 70 from both sides, we get
880-70 = 45d +70-70
810=45d
Dividing both sides by 45, we get
18=d.
Therefore,<em> 18 days Barry attended preschool last month.</em>
<em>Therefore, correct option is D option.</em>
<h3><em>D. 880 = 45d + 70; 18 days.</em></h3>In 90 minutes the population to grow to 700 organisms.
Given that,
A strand of bacteria has a doubling time of 15 minutes.
If the population starts with 10 organisms.
We have to determine,
How long would it take for the population to grow to 700 organisms?
According to the question,
A strand of bacteria has a doubling time of 15 minutes.
If the population starts with 10 organisms.
In 15 minutes strand of bacteria has a doubling time the population starts with 10 organisms.
In 15 minutes 20 bacteria for the population to grow.
In 30 minutes strand of bacteria has a doubling time the population starts with 20 organisms.
In 30 minutes 40 bacteria for the population to grow.
In 45 minutes strand of bacteria has a doubling time the population starts with 40 organisms.
In 45 minutes 80 bacteria for the population to grow.
In 60 minutes strand of bacteria has a doubling time the population starts with 80 organisms.
In 60 minutes 160 bacteria for the population to grow.
In 75 minutes strand of bacteria has a doubling time the population starts with 160 organisms.
In 75 minutes 320 bacteria for the population to grow.
In 90 minutes strand of bacteria has a doubling time the population starts with 320 organisms.
In 90 minutes 640 bacteria for the population to grow.
In 120 minutes strand of bacteria has a doubling time the population starts with 640 organisms.
In 120 minutes 1280 bacteria for the population to grow.
Hence, In 90 minutes the population to grow to 700 organisms.
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