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2 years ago

8

Working alone, Jack can do a puzzle in 5 hours. With his brother's help, the two can do the same puzzle in 2 hours. How long wou

ld it take Jack's brother to do the puzzle alone?

2 answers:

Ulleksa [173]2 years ago

8 0

Answer:

3 hours

Step-by-step explanation:

5 - 2 = 3

hoa [83]2 years ago

4 0

Answer:

3 hours and 20 minutes

Step-by-step explanation:

(I'm so sorry I forgot the work)

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"alan drives an average of 100 miles each week. his car can travel an average of 25 miles per gallon of gasoline. alan would lik

nydimaria [60]

First, list all the given information:
*100 miles/week
*25 miles/gallon
*$4/gallon
*weekly expenditure reduced by $5

The easiest approach to use here is the dimensional analysis. Cancel out like units if they appear both in the numerator and denominator side. Solve first the original cost. The solution is as follows:

100 miles/week * 1 gal/25 miles * $4/gal = $16/week

The reduced cost would be:
16 - 5 = (New average miles/week) * 1 gal/25 miles * $4/gal
New average miles/week = 68.75 miles/week

8 0

2 years ago

Read 2 more answers

Gibbs Baby Food Company wishes to compare the weight gain of infants using its brand versus its competitor’s. A sample of 40 bab

Leviafan [203]

Answer:

$z=\frac{(7.6-8.1)-0}{\sqrt{\frac{2.3^2}{40}+\frac{2.9^2}{55}}}}=-0.936$

The p value can be founded with this formula:

$p_v =P(z$

Since the p value is higher than the significance level provided of 0.05 we have enough evidence to FAIL to reject the null hypothesis and we can't conclude that the true mean for the Gibbs brand is significantly lower than the true mean for the competitor

Step-by-step explanation:

Information given

$\bar X_{1}=7.6$ represent the mean for Gibbs products

$\bar X_{2}=8.1$ represent the mean for the competitor

$\sigma_{1}=2.3$ represent the population standard deviation for Gibbs

$\sigma_{2}=2.9$ represent the sample standard deviation for the competitor

$n_{1}=40$ sample size for the group Gibbs

$n_{2}=55$ sample size for the group competitor

$\alpha=0.05$ Significance level provided

z would represent the statistic

Hypothesis to verify

We want to check if babies using the Gibbs brand gained less weight, the system of hypothesis would be:

Null hypothesis: $\mu_{1}-\mu_{2}=0$

Alternative hypothesis: $\mu_{1} - \mu_{2}< 0$

The statistic would be given by:

$z=\frac{(\bar X_{1}-\bar X_{2})-\Delta}{\sqrt{\frac{\sigma^2_{1}}{n_{1}}+\frac{\sigma^2_{2}}{n_{2}}}}$ (1)

Replacing the info given we got:

$z=\frac{(7.6-8.1)-0}{\sqrt{\frac{2.3^2}{40}+\frac{2.9^2}{55}}}}=-0.936$

The p value can be founded with this formula:

$p_v =P(z$

Since the p value is higher than the significance level provided of 0.05 we have enough evidence to FAIL to reject the null hypothesis and we can't conclude that the true mean for the Gibbs brand is significantly lower than the true mean for the competitor

5 0

2 years ago

Sarah wants to know this problem. What five times five

OleMash [197]

Five times fiver equals 25

8 0

2 years ago

Read 2 more answers

A farm had 480 acres more wheat than corn. After the farmers collected 80% of the wheat and 25% of the corn, the area of the whe

Sergio [31]

The area covered by corn is x
The area covered by wheat is (x+480)
After 80% of wheat was collected, the new area was:
20/10(x+480)
=1/5(x+480)
After 25% of the corn was collected, the new area was:
75/100x
=3/4x
New area equation will be:
(3/4)x=1/5(x+480)+300
(3/4x)=(1/5)x+96+300
solving for x we get:
11/20x=396
x=720
thus the original area of corn was 720 acres
Original area of wheat was 720+480=1200 acres

7 0

2 years ago

Molly wants to put a fence around an area. The fence will follow the diagram of the triangle shown below.

IgorC [24]

Molly would need 43 feet of fencing to fence the area.

Step-by-step explanation:

We can see that the area is in the form of a right-angled triangle. Since only two sides of the triangle is given, we could utilise Pythagoras theorem to our advantage to find out the third side.

In Δ ABC

AB² (base) + AC² (perpendicular) = BC² (hypotenuse)

Substituting the values of AB as 10 feet and BC as 18 feet

AC²= BC²- AB ²

∴AC²= 224

∴AC= 14.96 cm

Amount of fence required by molly would equal perimter of the area.

⇒The perimeter of the area would equal AB+BC+AC

⇒Summing up the values of AB, AC and BC

Perimeter= 10+14.96+18= 42.96 feet which is about 43 feet

Hence, Molly would require 43 feet of fencing.

3 0

2 years ago