What does S in Math means?

Going against the current, a boat takes 6 hours to make a 120-mile trip. When the boat travels with the current on the return tr

dybincka [34]

Against the current it was going 20mph with the current it was going 24mph , it should be x+y because rate of the boat and rate of the current combined equals the rate of the boat WITH the current

6 0

3 years ago

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Find the confidence interval with a 90% level of confidence. In October 2010, Gallup Poll asked 510 randomly sampled adults the

ratelena [41]

Answer:

90% confidence interval for the percent of the population who consider the death penalty to be "fair" is [54.4% , 61.6%].

Step-by-step explanation:

We are given that in October 2010, Gallup Poll asked 510 randomly sampled adults the question, "Generally speaking, do you believe the death penalty is applied fairly or unfairly in this country today?"

Of these, 58% answered "fairly", 36% said "unfairly" and 7% said they didn't know.

Firstly, the Pivotal quantity for 90% confidence interval for the population proportion is given by;

P.Q. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ~ N(0,1)

where, $\hat p$ = sample proportion who answered death penalty "fair" = 58%

n = sample of adults = 510

p = population percentage

Here for constructing 90% confidence interval we have used One-sample z test for proportions.

So, 90% confidence interval for the population percentage, p is ;

P(-1.645 < N(0,1) < 1.645) = 0.90 {As the critical value of z at 5% level

of significance are -1.645 & 1.645}

P(-1.645 < $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < 1.645) = 0.90

P( $-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < $\hat p-p$ < $1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ) = 0.90

P( $\hat p-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < p < $\hat p+1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ) = 0.90

90% confidence interval for p = [ $\hat p-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ , $\hat p+1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ]

= [ $0.58-1.645 \times {\sqrt{\frac{0.58(1-0.58)}{510} } }$ , $0.58+1.645 \times {\sqrt{\frac{0.58(1-0.58)}{510} } }$ ]

= [0.544 , 0.616]

Therefore, 90% confidence interval for the percent of the population who consider the death penalty to be "fair" is [54.4% , 61.6%].

6 0

3 years ago

I will mark brainliest

butalik [34]

Answer: 16875

Step-by-step explanation:

Let the price of the washing machine be x.

Since she loses 20% in the bargain, this implies that she sold it at (100% - 20%) = 80%.

Therefore, 80% of x = 13500

0.8 × x = 13500

0.8x = 13500

Divide both side by 0.8

0.8x/0.8 = 13500/0.8

x = 16875

Therefore, the price at which she bought the washing machine is 16875 rupees.

6 0

2 years ago

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jesse walks 3 miles per hour to school.the school is 1.5 miles away.How long would it take jesse to walk to school

Pavlova-9 [17]

1 hour 30 minutes!
Please mark this the brainlest answer

5 0

3 years ago

The roof of the building shown below has a span of 48 feet. The rafters upon which the roof is laid are 30 feet long, including

anyanavicka [17]

Solution :

Given :

Span of the roof = 48 feet

Length of the rafter = 30 feet (including the 4 feet overhung)

So, for the 30 feet long rafter, 26 feet will be rafter length from the high point of the roof to the edge of the roof and 4 feet will be the roof overhung.

Therefore, the horizontal span per rafter is

$=\frac{48}{2}$