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4 years ago

6

a store sells gift cards in preset amount. You can purchase gift cards for $20 or $30 . You spent $380 on gift cards. let x be t

he number of gift cards for $20 And let y be your gift cards for $30 . Write an equation in standards for to represent this situation

1 answer:

RSB [31]4 years ago

8 0

Y * 30 = 180 + x * 20 = 200
in other words You bought 6 $30 dollar gift card which equals 180 and u bought 10 $20 gift cards which equals 200.

180 + 200 = 380
:D

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A rectangular room is 13 more than twice its width, and its area is 24 cm squared . What are the dimensions of the rectangle?

aleksandrvk [35]

8/1/15 would be the dimensions

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4 years ago

Two machines are used for filling glass bottles with a soft-drink beverage. The filling process have known standard deviations s

stellarik [79]

Answer:

a. We reject the null hypothesis at the significance level of 0.05

b. The p-value is zero for practical applications

c. (-0.0225, -0.0375)

Step-by-step explanation:

Let the bottles from machine 1 be the first population and the bottles from machine 2 be the second population.

Then we have $n_{1} = 25$ , $\bar{x}_{1} = 2.04$ , $\sigma_{1} = 0.010$ and $n_{2} = 20$ , $\bar{x}_{2} = 2.07$ , $\sigma_{2} = 0.015$ . The pooled estimate is given by

$\sigma_{p}^{2} = \frac{(n_{1}-1)\sigma_{1}^{2}+(n_{2}-1)\sigma_{2}^{2}}{n_{1}+n_{2}-2} = \frac{(25-1)(0.010)^{2}+(20-1)(0.015)^{2}}{25+20-2} = 0.0001552$

a. We want to test $H_{0}: \mu_{1}-\mu_{2} = 0$ vs $H_{1}: \mu_{1}-\mu_{2} \neq 0$ (two-tailed alternative).

The test statistic is $T = \frac{\bar{x}_{1} - \bar{x}_{2}-0}{S_{p}\sqrt{1/n_{1}+1/n_{2}}}$ and the observed value is $t_{0} = \frac{2.04 - 2.07}{(0.01246)(0.3)} = -8.0257$ . T has a Student's t distribution with 20 + 25 - 2 = 43 df.

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c. The 95% confidence interval for the true mean difference is given by (if the samples are independent)

$(\bar{x}_{1}-\bar{x}_{2})\pm t_{0.05/2}s_{p}\sqrt{\frac{1}{25}+\frac{1}{20}}$ , i.e.,

$-0.03\pm t_{0.025}0.012459\sqrt{\frac{1}{25}+\frac{1}{20}}$

where $t_{0.025}$ is the 2.5th quantile of the t distribution with (25+20-2) = 43 degrees of freedom. So

$-0.03\pm(2.0167)(0.012459)(0.3)$ , i.e.,

(-0.0225, -0.0375)

8 0

3 years ago

Help Please......<br>...<br>...<br>..

vfiekz [6]

Answer:

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Step-by-step explanation:

First change the mixed numbers into an improper fractions.

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$27\frac{1}{3}$ = $\frac{82}{3}$ 27 x 3 = 81 + 1 = 82

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2 and 3 have 6

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3 years ago

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Blizzard [7]

Answer:

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the actual solution to the system of equations is (-(64/27),(56/9)).

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9:15

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