What is the value of x?

A rectangle has a length 3 times the width. What is the perimeter in terms of x?

Marina CMI [18]

Answer:

Perimeter is equal to all four sides added together.

Length = 3W; L=3W

So

P = 2(W) + 2(L) substitute the equation for length above you get

P = 2(W) + 2(3W) and combine

P = 2W + 6W = 8W; put in what the perimeter is and solve for W

66 = 8W, so W = 8.25

W = 8.25, L = 24.75

7 0

4 years ago

Jamie has 100 milliliters of a 50% isopropyl alcohol solution. How many milliliters of a 96% isopropyl alcohol solution does she

serious [3.7K]

Answer:

318.2 ml

Step-by-step explanation:

Jamie has 100 ml of a 50% isopropyl alcohol solution.

She wants to prepare a solution of 85% by adding 96% solution of isopropyl alcohol solution.

Let the amount of 96% solution required = x ml

Final amount of 85% isopropyl alcohol solution = (100 + x) ml

Therefore, equation for this situation will be,

100 × (50%) + (x) × (96%) = (100 + x) × (85%)

100(0.5) + 0.96x = 0.85(100 + x)

50 + 0.96x = 85 + 0.85x

0.96x - 0.85x = 85 - 50

0.11x = 35

x = $\frac{35}{0.11}$

x = 318.18 ml

≈ 318.2 ml

Therefore, she will require 318.2 ml of 96% isopropyl alcohol solution.

4 0

3 years ago

I really need to know how long it takes the large pipe on its own

Andreyy89

s = hours it takes the small pipe on its own.

L = hours it takes the large pipe on its own.

we know the small pipe can do it in 11 hours total, so s = 11, so, how much of the whole job has the small done in 1 hour only?

well, if it takes 11 hours to do the whole thing, in 1 hour it has done only 1/11 of the whole job.

we know both pipes working together can do it in 6 hours flat. So in 1 hour only, both of them have done only 1/6 of the whole thing.

in that 1 hour, how much has the large one done? well, it has only done 1/L of the job.

$\bf \stackrel{\textit{how much has it been done by both in 1 hour}}{\stackrel{\stackrel{small}{rate}}{\cfrac{1}{s}}+\stackrel{\stackrel{large}{rate}}{\cfrac{1}{L}}~~=~~\stackrel{job}{\cfrac{1}{6}}} \\\\\\ \cfrac{1}{11}+\cfrac{1}{L}=\cfrac{1}{6}\implies \stackrel{\textit{multiplying both sides by }\stackrel{LCD}{66L}}{6L+66=11L}\implies 66=5L \\\\\\ \cfrac{66}{5}=L\implies 13\frac{1}{5}=L\impliedby \textit{13 hours and 12 minutes}$

and you can round that up as needed.

7 0

4 years ago

Factor 16x^2 + 49. Check your work.

Shtirlitz [24]

Answer:

$16x^2+49=(x-\frac{7i}{4})(x+\frac{7i}{4})$

Step-by-step explanation:

Given : Expression $16x^2+49$

To find : Factor the expression ?

Solution :

The given expression is a quadratic function $y=ax^2+bx+c$ the solution is $x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

On comparing with general form,

a=16, b=0, c=49

Substitute in the formula,

$x=\frac{-0\pm\sqrt{0^2-4(16)(49)}}{2(16)}$

$x=\frac{\pm\sqrt{-3136}}{32}$

$x=\frac{\pm56i}{32}$

$x=\frac{56i}{32},\frac{-56i}{32}$

$x=\frac{7i}{4},\frac{-7i}{4}$

Factors are $(x-\frac{7i}{4}),(x+\frac{7i}{4})$

Therefore, $16x^2+49=(x-\frac{7i}{4})(x+\frac{7i}{4})$

4 0

4 years ago

The mean time it takes to walk to the bus stop is 8 minutes (with a standard deviation of 2 minutes) and the mean time it takes

kifflom [539]

We have been given for a normal distribution the mean time it takes to walk to the bus stop is 8 minutes with a standard deviation of 2 minutes. And the mean time it takes for the bus to get to school is 20 minutes with a standard deviation of 4 minutes.

(a) Average time that it would take reach school can be obtained by adding the average times.

8+20 = 28 minutes.

(b) Standard deviation of the trip to school can be found as:

$\sigma =\sqrt{2^{2}+4^{2}}=\sqrt{4+16}=\sqrt{20}=4.47$