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3 years ago

5

What is the surface area ?

2 answers:

vodomira [7]3 years ago

6 0

The answer will be 50 because if you are doing Area the formula is length times width therefore you would multiply all the numbers and you will end up with 50 feet cubed

Maurinko [17]3 years ago

5 0

Answer:

C 90 ft³

Step-by-step explanation:

surface area = 2 (h · l + h · w + l · w)

The measurements of this rectangular prism is:

h = 2

w = 5

l = 5

2 (2 · 5 + 2 · 5 + 5 · 5)

Using PEMDAS, we have:

2 (10 + 10 + 25)

2 (45)

90 ft cubed

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Jeff bicycles 126 miles at the rate of r mph. The same trip would have taken 2 hours longer if he had decreased his speed by 4 m

weqwewe [10]

Given Information:

Distance = 160 miles

Required Information:

Rate = r = ?

Answer:

Rate = r = 20 mph

Step-by-step explanation:

Recall that the rate is given by

Rate = distance/time

$r = \frac{d}{t} \\\\t = \frac{d}{r} \\\\t = \frac{160}{r} \\\\$

It is given that the same trip would have taken 2 hours longer if he had decreased his speed by 4 mph.

Mathematically,

$\frac{160}{(r-4)} = \frac{160}{r} + 2 \\\\$

Simplify the equation

$\frac{160}{(r-4)} - \frac{160}{r} = 2 \\\\\frac{160r - 160(r-4)}{r(r-4)} = 2 \\\\\frac{160r - 160r+640)}{r(r-4)} = 2 \\\\160r - 160r+640 = r(r-4) (2) \\\\640 = r(r-4) (2) \\\\640 = (r^2 - 4r) (2) \\\\640 = 2r^2 - 8r \\\\2r^2 - 8r-640 =0 \\\\2(r^2 - 4r-320) =0 \\\\r^2 - 4r-320 =0 \\\\$

Now we are left with a quadratic equation.

We may solve the quadratic equation using the factorization method

$r^2 - 4r-320 =0 \\\\r^2-20r+16r-320=0 \\\\r(r-20)+16(r-20)=0 \\\\(r-20) (r+16)=0 \\\\$

So,

$(r-20) = 0 \\\\r = 20 \\\\$

OR

$(r+16)=0 \\\\r = -16 \\\\$

Since rate cannot be negative, discard the negative value of r

Therefore, the rate is

$r = 20 \: mph$

3 0

4 years ago

What is 12,430,000 in expanded form?

Nady [450]

10,000,000+2,000,000+400,000+30,000

3 0

4 years ago

How do I find the GCF OF 3 numbers

kolezko [41]

Keep diving each of them by a number and see if it matches. For example I have 25, 50, and 100. The gcf is going to be 5.

6 0

3 years ago

The half-life of a certain tranquilizer in the bloodstream is 47 hours. How long will it take for the drug to decay to 93% of

GaryK [48]

Answer:

It will take 4.84 hours for the drug to decay to 93% of the original dosage.

Step-by-step explanation:

We are given that the half-life of a certain tranquilizer in the bloodstream is 47 hours.

The given exponential model is: $A = A_0 e^{kt}$

Now, we know that A becomes half after 47 hours which means that;

$A = 0.5 A_0$

Using this in the above equation we get;

$A = A_0 e^{kt}$

$0.5 A_0 = A_0 e^{(k\times 47)}$ where t = 47 hours

$\frac{0.5 A_0}{A_0} = e^{(47k)}$

$0.5 = e^{47k}$

Taking log on both sides we get;

$ln(0.5) = ln(e^{47k})$

$ln(0.5) =47k$

$k = \frac{ln(0.5)}{47}$

k = -0.015

Now, the time it will take for the drug to decay to 93% of the original dosage is given by;

$0.93 = e^{kt}$ where t is the required time

$0.93 = e^{(-0.015 \times t)}$

Taking log on both sides we get;

$ln(0.93) = ln(e^{-0.015t})$

$ln(0.93) =-0.015t$

$t = \frac{ln(0.93)}{-0.015}$

t = 4.84 hours

Hence, it will take 4.84 hours for the drug to decay to 93% of the original dosage.

8 0

4 years ago

What is the slope of the line shown below? (4, 8) (2, 4)

Zinaida [17]

Answer:

Slope = 2

Step-by-step explanation:

Slope is the change in y/change in x. So (8-4)/4-2)=2.

5 0

3 years ago

Read 2 more answers