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3 years ago

Question Help

Mathematics

1 answer:

lorasvet [3.4K]3 years ago

6 0

Answer:

The speed of the boat is 20 km/hr

Step-by-step explanation:

Let s be the speed of boat in still water

Let d be the distance

Upstream speed = s-4

Jane took 30 min to drive her boat upstream to water-ski at her favorite spot.

So, Distance traveled in upstream = $Speed \times time =(s-4) \times \frac{30}{60}$

Downstream speed = s+4

So, Distance traveled in downstream = $Speed \times time =(s+4) \times \frac{20}{60}$

So, $(s-4) \times \frac{30}{60}=(s+4) \times \frac{20}{60}$

30s-120=20s+80

10s=200

s=20

Hence The speed of the boat is 20 km/hr

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A pen company averages 1.2 defective pens per carton produced (200 pens). The number of defects per carton is Poisson distribute

nlexa [21]

Answer:

a. P(x = 0 | λ = 1.2) = 0.301

b. P(x ≥ 8 | λ = 1.2) = 0.000

c. P(x > 5 | λ = 1.2) = 0.002

Step-by-step explanation:

If the number of defects per carton is Poisson distributed, with parameter 1.2 pens/carton, we can model the probability of k defects as:

$P(k)=\frac{\lambda^{k}e^{-\lambda}}{k!}= \frac{1.2^{k}\cdot e^{-1.2}}{k!}$

a. What is the probability of selecting a carton and finding no defective pens?

This happens for k=0, so the probability is:

$P(0)=\frac{1.2^{0}\cdot e^{-1.2}}{0!}=e^{-1.2}=0.301$

b. What is the probability of finding eight or more defective pens in a carton?

This can be calculated as one minus the probablity of having 7 or less defective pens.

$P(k\geq8)=1-P(k$

$P(0)=1.2^{0} \cdot e^{-1.2}/0!=1*0.3012/1=0.301\\\\P(1)=1.2^{1} \cdot e^{-1.2}/1!=1*0.3012/1=0.361\\\\P(2)=1.2^{2} \cdot e^{-1.2}/2!=1*0.3012/2=0.217\\\\P(3)=1.2^{3} \cdot e^{-1.2}/3!=2*0.3012/6=0.087\\\\P(4)=1.2^{4} \cdot e^{-1.2}/4!=2*0.3012/24=0.026\\\\P(5)=1.2^{5} \cdot e^{-1.2}/5!=2*0.3012/120=0.006\\\\P(6)=1.2^{6} \cdot e^{-1.2}/6!=3*0.3012/720=0.001\\\\P(7)=1.2^{7} \cdot e^{-1.2}/7!=4*0.3012/5040=0\\\\$

$P(k$

c. Suppose a purchaser of these pens will quit buying from the company if a carton contains more than five defective pens. What is the probability that a carton contains more than five defective pens?

We can calculate this as we did the previous question, but for k=5.

$P(k>5)=1-P(k\leq5)=1-\sum_{k=0}^5P(k)\\\\P(k>5)=1-(0.301+0.361+0.217+0.087+0.026+0.006)\\\\P(k>5)=1-0.998=0.002$

5 0

3 years ago

D. 9x-X+5x =260<br> Bx= 200

yan [13]

Answer:

We first must solve for x

$9x-x+5x=260\\13x=260\\x=30$

When we have x, we put it in to the second equation

$Bx=200\\\\B=\frac{200}{x} \\\\B=\frac{200}{30}\\\\B=\frac{20}{3}$

8 0

2 years ago

Tabo earns k4200 per month. His budget is k2500 for food, k300 for rent, k150 for clothes and k100 for other things. (a) how muc

Mademuasel [1]

Answer:

a) K3050 and b) K1150

Step-by-step explanation:

a) Add all his expenditures

i.e: K300+K150+K100

=K3050

b) Subtract the remaining of his spendings from the total

i.e: K4209 - K3050

=K1150

3 0

3 years ago

Is .21 (with only the one repeating) a rational number? please explain why! thanks!

Nostrana [21]

21 is a rational number because it is an integer, which can be converted into a fraction.

<u>Step-by-step explanation:</u>

When a denominater and numerator are integers and gives a quotient then it is a rational number.

21/1, where 21 is denominator and 1 is numerator the quotient is 21. Therefore 21 is a rational number which can also be considered as a ratio.

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3 years ago

Which angle is congruent to 5?

solniwko [45]

Answer:

Angle #4

Step-by-step explanation:

4 & 5 are equal, and opposite.

1 & 2 are also congruent by this standard.

6 0

3 years ago