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8090 [49]
3 years ago
9

Johnny and his father go fishing at 5:00 AM. After motoring 6 km upstream, Johnny writes a letter to his friend, puts the letter

in a bottle and drops it into the river. the bottle floats in the current and reaches at 7 : 40 AM the point where Johnny and his father began the trip. If the speed of the boat in still water is 9 km/h, what is the speed of the river current?
Mathematics
1 answer:
FromTheMoon [43]3 years ago
4 0

Answer:

4.5

Step-by-step explanation:

Probably too late for your RSM homework, but here is the solution:

6/(9-x) [Time they motored upstream] +6/x [Time it took the bottle to get back to the starting point] = 8/3 [Total Time]

Simplify to 54/(x(9-x))=8/3

Cross multiply: 162=(8x)(9-x)

Simplify -x^2+9x=20.25

Multiply both sides by negative one and move 20.25 to the other side. x^2-9x+20.25=0

Solve and get 4.5 :D!

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Seth's family plans to drive 220 miles to their vacation spot. They would like to complete the drive in 4 hours. Find the averag
lions [1.4K]
Just divide 220 by 4 to get the answer. So the answer is 55.

Explanation:

220/4=55

If the drive needs to be completed in 4 hours and the drive is 220 miles then how much mph do they need to go

Miles/hours=miles per hour

Brainliest my answer if it helps you out
8 0
3 years ago
A manufacturing process is designed to produce bolts with a 0.25-in. diameter. Once each day, a random sample of 36 bolts is sel
Troyanec [42]

Answer:

0.6170

Step-by-step explanation:

Given that a manufacturing process is designed to produce bolts with a 0.25-in. diameter.

i.e. no of bolts which are produced as per standard is X means then

X is normal with mean = 0.250 and std dev = 0.04

No of bolts tested = 36

If this mean falls outside the interval (0.230,0.270) the production would be shut down.

i.e. P(|x-25|>0.20) =production shut down probability

P(|x-25|>0.20)\\=P(|Z|>0.5)\\=2(0.5-0.1915)\\= 0.6170

3 0
3 years ago
Find the value of y if the mean is 22 and 18 ( 2y+1), 10 and 20 is 15<br>​
Igoryamba

Answer:

2

Step-by-step explanation:

Mean = sum of data/sample size

Sum of data = 22 + 18 + 2y+1 + 10 + 20

Sample size = 5

Mean = 15

Substitute

15 = 22 + 18 + 2y+1 + 10 + 20/5

15*5 = 22 + 18 + 2y+1 + 10 + 20

75 = 70+2y+1

2y = 75-71

2y = 4

y = 4/2

y = 2

Hence the value of y is 2

8 0
3 years ago
1
Annette [7]

Answer:

c

Step-by-step explanation: If you do the math you can clearly see and I got the answer correct.

7 0
3 years ago
Help I will give 30 points help me out need ASAP please
Oksana_A [137]

Answer:

21 in.

Step-by-step explanation:

The radius is half of the diameter. The diameter (as shown) is 42 inches. Divide that by two to get 21 in.

6 0
3 years ago
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