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3 years ago

Amy is six years younger than Melody. Two years ago, Melody was three times as old as Amy. How old is Amy now?

Mathematics

2 answers:

Eduardwww [97]3 years ago

8 0

Answer:

Step-by-step explanation:

two years ago she was 4 and he is 3 times as old as her which is 12 add the 2 years ago now she is 14

Ugo [173]3 years ago

5 0

Answer:

Amy is 14 years old now.

Step-by-step explanation:

This one is a bit wordy, but try to break down the word problem.

Amy is six years younger than Melody. Two years ago, Melody was three times as old as Amy.

So, Melody was 6(3)+2. Melody was 18 two years ago, so add 2 to that number. Subtract the answer (which is 20) by 6. Therefore, Amy is 14.

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) The National Highway Traffic Safety Administration collects data on seat-belt use and publishes results in the document Occupa

asambeis [7]

Answer:

We conclude that there is a difference in seat belt use.

Step-by-step explanation:

We are given that of 1,000 drivers 16-24 years old, 79% said they buckle up, whereas 924 of 1,100 drivers 25-69 years old said they did.

Let $p_1$ = population proportion of drivers 16-24 years old who buckle up .

$p_2$ = population proportion of drivers 25-69 years old who buckle up .

So, Null Hypothesis, $H_0$ : $p_1-p_2$ = 0 {means that there is no significant difference in seat belt use}

Alternate Hypothesis, $H_A$ : $p_1-p_2\neq$ 0 {means that there is a difference in seat belt use}

The test statistics that would be used here Two-sample z proportion statistics;

T.S. = $\frac{(\hat p_1-\hat p_2)-(p_1-p_2)}{\sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1}+\frac{\hat p_2(1-\hat p_2)}{n_2} } }$ ~ N(0,1)

where, $\hat p_1$ = sample proportion of drivers 16-24 years old who buckle up = 79%

$\hat p_2$ = sample proportion of drivers 25-69 years old who buckle up = $\frac{924}{1100}$ = 84%

$n_1$ = sample of 16-24 years old drivers = 1000

$n_2$ = sample of 25-69 years old drivers = 1100

So, test statistics = $\frac{(0.79-0.84)-(0)}{\sqrt{\frac{0.79(1-0.79)}{1000}+\frac{0.84(1-0.84)}{1100} } }$

= -2.946

The value of z test statistics is -2.946.

Since, in the question we are not given with the level of significance so we assume it to be 5%. Now, at 0.05 significance level the z table gives critical values of -1.96 and 1.96 for two-tailed test.

Since our test statistics doesn't lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that there is a difference in seat belt use.

4 0

3 years ago

A certain type of chocolate bar is sold as follows.

Scrat [10]

Answer:

Step-by-step explanation:

You would never buy a 10-pack, because two 5-packs cost less.

To buy 3 bars you need a single bar and a pair of single bars for £0.82 + £0.82+ £0.41 = £2.05

To buy 30 bars you need 3 pairs of 5-bar packs = 3×£5.75 = £17.25

To buy the remaining 5 bars you need one 5-bar pack = £3

cost = £2.05 + £17.25 + £3 = £22.30

5 0

3 years ago

Shinto is serving pizza. He serves 1/5 of the pizza to one friend and 5/12 to another friend. If he had 9/10 of a pizza to start

never [62]

Answer: 17/60

Step-by-step explanation:

Change all of the fractions to have a common denominator:

LCM of 10, 12, 15 is 60

You get 12/60, 25/60, and 54/60.

54/60 is what he had at the start, and so you can just subtract what he gave away

54/60-12/60=42/60

42/60-25/60=17/60

17 is a prime number so you cannot simplify the fraction

3 0

3 years ago

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This is a line segment between two points on the circle or sphere which passes throught

yanalaym [24]

Answer:

diameter?

Step-by-step explanation:

4 0

3 years ago

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0.01x - 0.3y = 1

Phantasy [73]

Answer: your answer would be

x-30y=100 and 10y = x - 20

Step-by-step explanation:

6 0

3 years ago