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3 years ago

Lisa lit a candle with a height of 8 inches. When lit, this candle loses 10% of its original

Mathematics

1 answer:

hichkok12 [17]3 years ago

3 0

Answer:

1.25 hours or 1 hour and 15 minutes

Step-by-step explanation:

Question

Lisa lit a candle with a height of 8 inches. When lit, this candle loses 10% of its original height every hour.
Please complete the following sentence by writing the number in the blank. Until the candle has been burning for at least _______ hours, the height of Jennifer's candle will be more than 7 inches.

Candle looses 10% of 8 inches, it equals:

8*0.1 = 0.8 inches an hour

Let x be required time, then:

8 - 0.8x > 7
0.8x < 8 - 7
0.8x < 1
x < 1/0.8
x < 1.25
or 1 hour 15 minutes

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Describe different ways in which a plane might intersect the cylinder and the cross section that results?

lutik1710 [3]

Answer : If it is perpendicular to the axis, then a circle. If it is at an angle to the axis, then an ellipse. If it is parallel to the axis, then two parallel lines. Those are the only 3 cases that I can think of.

Hope this helps.

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3 years ago

A ski gondola carries skiers to the top of a mountain. assume that weights of skiers are normally distributed with a mean of 199

Allushta [10]

A) maximum mean weight of passengers = load limit ÷ number of passengers

maximum mean weight of passengers = 3750 ÷ 25 = 150lb

B) First, find the z-score:
z = (value - mean) / stdev
 = (150 - 199) / 41
 = -1.20

We need to find P(z > -1.20) = 1 - P(z < -1.20)

Now, look at a standard normal table to find P(z < -1.20) = 0.11507, therefore:
P(z > -1.20) = 1 - 0.11507 = 0.8849

Hence, the probability that the mean weight of 25 randomly selected skiers exceeds 150lb is about 88.5% 

C) With only 20 passengers, the new maximum mean weight of passengers = 3750 ÷ 20 = 187.5lb

Let's repeat the steps of point B)

z = (187.5 - 199) / 41
 = -0.29

P(z > -0.29) = 1 - P(z < -0.29) = 1 - 0.3859 = 0.6141

Hence, the probability that the mean weight of 20 randomly selected skiers exceeds 187.5lb is about 61.4%

D) The mean weight of skiers is 199lb, therefore:
number of passengers = load limit ÷ mean weight of passengers
 = 3750 ÷ 199
 = 18.8
The new capacity of 20 skiers is safer than 25 skiers, but we cannot consider it safe enough, since the maximum capacity should be of 18 skiers.

4 0

2 years ago

Annie buys a picnic table priced at $407. If the sales tax is 6%, what will be the total cost including tax?

Oksi-84 [34.3K]

Answer:

-$407

-tax:6%

407 times 6 divided by 100

413/100

4.13

407 plus 4.13

$411.13

3 0

2 years ago

How the heck do I do this? And what’s the answer?

stira [4]

Answer:

Option A

Step-by-step explanation:

We need to find two expressions that, when simplified, give the same results.

1) First, simplify the expression stated in the question. Multiply each of the terms in the parentheses by the number that is next to them. This would mean you have to multiply both 9x and -6 by $\frac{2}{3}$ . You also have to multiply $\frac{1}{2}x$ and $-\frac{1}{2}$ by 4. Then, simplify.

$\frac{2}{3}(9x-6) + 4 (\frac{1}{2} x - \frac{1}{2})\\\frac{18}{3}x- \frac{12}{3} + \frac{4}{2}x -\frac{4}{2} \\6x - 4 + 2x - 2$

2) Now, combine the like terms.

$6x - 4 + 2x - 2$

$8x - 6$

So, we need to find which of the expressions listed equal 8x - 6.

3) Let's try option A. Do the same as before. Multiply each of the terms in the parentheses by the number that is next to them. So, multiply 4x and -12 by $\frac{3}{4}$ . Also, multiply 30x and 18 by $\frac{1}{6}$ . Then, combine like terms and simplify.