exponential word problems

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• $y\ =\ 5000\left(1-\frac{30}{100}\right)^t$

• $y\ =\ 5000\left(1+\frac{30}{100}\right)^t$

• $y\ =\ 30\left(1-\frac{5000}{100}\right)^t$

• $y\ =\ 30\left(1+\frac{5000}{100}\right)^t$

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CCSS.HSF.LE.A.2

Write an equation that models the following situation:

Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

(HINT: Write out the equation on a separate piece of paper and hen simplify inside the parenthesis)

• y=6(0.14)^x

• y=6(1+14)^x

• y=6(1.14)^x

• y=6(0.86)^x

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CCSS.HSF.LE.A.2

You buy a new computer for $2100. The computer decreases by 50% annually. Which function represents the situation?

•  $y\ =\ 2100\left(1-\frac{50}{100}\right)^t$  

•  $y\ =\ 2100\left(1+\frac{50}{100}\right)^t$  

•  $y\ =\ 50\left(1-\frac{2100}{100}\right)^t$  

•  $y\ =\ 50\left(1+\frac{2100}{100}\right)^t$  

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CCSS.HSF.LE.A.2

You have inherited land that was purchased for $30,000 in 1960. The value of the land increased by approximately 5% per year. Write an equation to represent the situation:

• $f\left(x\right)\ =\ 30,000\left(1\ +\ \frac{5}{100}\right)^t$

• $f\left(x\right)\ =\ 30,000\left(1\ -\ \frac{5}{100}\right)^t$

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CCSS.HSF-BF.A.1A

Is this exponential growth or decay?

• Growth because a=1

• Growth because there is no a

• Decay because b=0.5

• Neither because a=0

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CCSS.HSF-IF.C.8B

Is this exponential growth or decay?

• Growth, because of 7

• Growth because of 1.2

• Decay, because of 1.2

• Decay because of 7

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CCSS.HSF-IF.C.8B

Pick the equation that is exponential decay

• y=2000(0.88)

• y=-4x

• y=0.5(1.88)

• y= -7+10x

Tags

CCSS.HSF-LE.A.1A

The number of mosquitoes at the beginning of the summer was 4,000. The population of mosquitoes is expected to grow at a rate of 25% a month. How many mosquitoes will there be after 4 months?

• 9765

• 9006

• 5433

• 9766

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CCSS.HSF.BF.A.2

In an exponential function, what does the 'a' represent?

• SLOPE

• RATE OF CHANGE

• INITIAL AMOUNT

• COMMON RATIO

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CCSS.HSF.LE.B.5

The mice population is 25,000 and is decreasing by 20% each year. What will be the mice population after 3 years?

• 12,800

• 15,777

• 102, 475

• 2,500

Tags

CCSS.HSF-LE.A.1C