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2 years ago

The price of a cd was decreased by 20% to £7.68. What was the price before the decrease?

Mathematics

1 answer:

love history [14]2 years ago

8 0

Answer:

£9.6

Step-by-step explanation:

x = the original price of a CD

£x = 100% of the original price

The price of a CD was decreased by 20% to £7.68.

This means:

£7.68 = 100% - 20%

£7.68 = 80% of the original price

From this, we will find 1% of the original price.

£7.68 ÷ 80 = 1%

£0.096 = 1%

Since the original price ( x ) = 100% of the original price, we will find 100% of the original price.

£0.096 × 100 = 100%

£9.6 = 100%

Therefore, the original price of a CD = £9.6

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Please answer these two questions on ratios.

Kruka [31]

1. first you have to find what they ran so what I did was take 28.5 km and divided by 3 because the ratio is 5:2 and 3 is the number difference. 28.5 km divided by 3 = 9.5 so every ratio is going into a 9.5 km part. For example, if the ratio was 2:1 the km ratio would be 19 km: 9.5 km. so I to 9.5 x 5=47.5 km and 9.5*2=19 km
so the 5:2 ratio is equal to 47.5 km : 19 km
The combined running distance would be 66.5 km

2. If the recommended ratio 5:2:3 and Kate wants to have 22 grams of protein(middle) that means her carbohydrates and fat would have to go up 2 x11 =22 so you would do the 5:2:3 ratio and times all three by 11. so the new ratio is 55:22:33. the 55 are your carbohydrates, the 22 are your proteins, and the 33 are your fats. The new ratio is 55:22:33

If Kate plans to eat 22g of protein she woulg have to have 55g of carbohydrates with it. Also she will have to have 33g of fats.

Hope this helps!
Tell me if these are correct.

4 0

2 years ago

on the grid below, draw and label an aquarium shaped like a rectangular prism with a volume of 8,000 cubic inches. (Hint: A cube

n200080 [17]

If you want an aquarium in shape of a cube with volume of 8000, then use the formula for volume of cube to find the length of one side:
V = s^3
where
s = side length
Substitute,
8000 = s^3
s = cuberoot(8000)
s = 20 inches

Well, if you have to draw this on a graphing paper, you should first make a scale to fit the drawing, like 1 inch = 0.5 cm, so a side length of 20 inches is equivalent to 10 cm on your graphing paper.

Hope this helped!

3 0

2 years ago

Operations: Housekeeping Math Quiz

masha68 [24]

Answer:

Total time = 63 hours

Step-by-step explanation:

First, let us write out the information in the question:

rate at which rooms are cleaned = 20 mins/room

number of rooms = 175

one-fifth of the rooms take 40% longer to clean

Next, let us convert the extra time taken to clean the rooms from percentage to time.

40% of normal cleaning time = 40% of 20

= 40/100 × 20 = 0.4 × 20 = 8 minutes

∴ onw-fifth of the rooms take an extra 8 minutes = 28 minutes in total

Next, let us calculate how many of those rooms in the total 175 takes the extra cleaning time:

one-fifth of the rooms takes 28 minutes to clean means that:

1 in every 5 rooms out of the 175 rooms take 28 minutes to clean

∴ Number of rooms with extra cleaning time = 1/5 of 175

= 1/5 × 175 = 0.2 × 175 = 35

∴ 35 rooms take 28 minutes each to be cleaned.

Now let us calculate the total cleaning time:

if 35 rooms take the extra cleaning time, then the number of rooms that have the normal cleaning time is as follows:

175 - 35 = 140

Total time:

140 rooms taking 20 minutes per room = 140 × 20 = 2,800 munites

35 rooms taking 28 minutes per room = 35 × 28 = 980 minutes

Total cleaning time = 2800 + 980 = 3780 minutes

converting to hours (1 hour = 60 minutes)

∴ 3780 minutes = 3780 ÷ 60 = 63 hours (2 days and 15 hours)

8 0

2 years ago

Statistics In the manual “How to Have a Number One the Easy Way,” it is stated that a song “must be no longer than three minutes

dimaraw [331]

Answer:

We conclude that the sample is from a population of songs with a mean greater than 210 seconds.

Step-by-step explanation:

We are given that a simple random sample of 40 current hit songs results in a mean length of 252.5 seconds.

Assume that the standard deviation of song lengths is 54.5 sec.

Let $\mu$ = population mean length of the songs

So, Null Hypothesis, $H_0$ : $\mu$ $\leq$ 210 seconds {means that the sample is from a population of songs with a mean smaller than or equal to 210 seconds}

Alternate Hypothesis, $H_A$ : $\mu$ > 210 seconds {means that the sample is from a population of songs with a mean greater than 210 seconds}

The test statistics that will be used here is One-sample z-test statistics because we know about population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample mean length of songs = 252.5 seconds

$\sigma$ = population standard deviation = 54.5 seconds

n = sample of current hit songs = 40

So, the test statistics = $\frac{252.5-210}{\frac{54.5}{\sqrt{40} } }$

= 4.932

The value of z-test statistics is 4.932.

Now, at 0.05 level of significance, the z table gives a critical value of 1.645 for the right-tailed test.

Since the value of our test statistics is more than the critical value of z as 4.932 > 1.645, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region.

Therefore, we conclude that the sample is from a population of songs with a mean greater than 210 seconds.

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2 years ago

A group of 85 people were asked whether or not they prefer a bagel or a muffin for breakfast and whether or not they prefer milk

gladu [14]

Answer:

The answer(s) would be WY/WZ, or WYZ (If this is multiple choice)

Step-by-step explanation:

The reasoning is that in the "IRL Equation" the polls showed that orange juice was prefered over milk, and didn't matter whether they wanted a bagel or muffin. All that matters in this equation is that it is one sided (For the 1st poll that is) and now you are able to narrow down the possibilities of the answer(s).

5 0

2 years ago