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2 years ago

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Dave walked to his friend's house at a rate of 4 mph and returned back biking at a rate of 10 mph. If it took him 18 minutes lon

ger to walk than to bike, what was the total distance of the round trip?
I need help on it

1 answer:

katrin [286]2 years ago

6 0

Answer:

4 miles

Step-by-step explanation:

<u>Walking:</u>

Distance = d miles

Rate = 4 mph

Time = t hours

$d=4\cdot t$

<u>Biking:</u>

Distance = d miles

Rate = 10 mph

Time $=t-\dfrac{18}{60}=t-0.3$ hours (convert minutes to hours)

$d=10\cdot (t-0.3)$

Hence,

$4t=10(t-0.3)\\ \\4t=10t-3\\ \\4t-10t=-3\\ \\-6t =-3\\ \\6t=3\\ \\t=\dfrac{3}{6}=\dfrac{1}{2}=0.5\ hour$

Therefore, the distance to friend's house is

$d=4\cdot 0.5=2\ miles$

and the total distance of the round trip is

$2+2=4\ miles$

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Complete Question

The lifespans of lions in a particular zoo are normally distributed. The average lion lives 12.5 years; the standard deviation is 2.4 years. Use the empirical rule (68-95-99.7\%)(68−95−99.7%) to estimate the probability of a lion living between 5.3 to 10. 1 years.

Answer:

Thehe probability of a lion living between 5.3 to 10. 1 years is 0.1585

Step-by-step explanation:

The empirical rule formula states that:

1) 68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.

2) 95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.

3) 99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ.

Mean is given in the question as: 12.5

Standard deviation : 2.4 years

We start by applying the first rule

1) 68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.

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We apply the second rule

2) 95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.

μ – 2σ

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5.3 years corresponds to one side of 99.7%

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And 10.1 years corresponds to one side of 68%

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Answer:

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Let

x ----> the number of 7th students on the Jackson Middle School basketball teams

y ----> the number of 8th students on the Jackson Middle School basketball teams

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2 years ago

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