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ELEN [110]
3 years ago
15

A fisherman traveled in a boat from point N upstream. After having traveled 6 km, he stopped rowing and 2 hour 40 min after firs

t leaving N, he was brought back to N by the current. Knowing that the speed of the boat in still water is 9 km/hour, find the speed of the river’s current.
Mathematics
2 answers:
Over [174]3 years ago
4 0
The current is 21.6km per hour
ArbitrLikvidat [17]3 years ago
3 0

upstream means going in opposite direction of river's current

downstream means going in same direction of river's current

Let the speed of river's current be x km/hour

so net speed of boat in upstream = (9-x) km/hour

net speed of boat in downstream = (9+x) km/hour

total time taken = 2 hours 40 minutes = 8/3 hours

total time taken = time in upstream + time in downstream

( time = distance / speed)

8/3 = 6/(9-x) + 6/(9+x)

solving for x

x = 6.36 km/hour

so speed of river's current = 6.36 km/hour


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What is the answer to 19+x/2=4?
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multiply 2 on both sides
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19+x=8
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3 years ago
kate takes 48 minutes to get to the park. if she gets to the park at 2:32 what time did she leave for the park
olya-2409 [2.1K]

Answer:

1:44

Step-by-step explanation:

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3 years ago
Carolyn swim 35 laps in 1/2 hour. How far will she swim in 4 hours? Please help.
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3 0
3 years ago
Read 2 more answers
Find values a and b that satisfy a∙〈5,-4,0〉+b∙〈2,2,-3〉=〈11,-16,-6〉.
WARRIOR [948]

The right hand side of the equation is 〈11 , -16 , 6〉

The values of a and b are a = 3 , b = -2

Step-by-step explanation:

If n . <a , b> + m . <c , d> = < x , y>, then

  • na + mc = x
  • nb + md = y

∵ a  ∙〈5 , -4 , 0〉 + b ∙ 〈2 , 2 , -3〉 = 〈11 , -16 , 6〉

- By using the rule above

∴ a(5) + b(2) = 11 ⇒ (1)

∴ a(-4) + b(2) = -16 ⇒ (2)

∴ a(0) + b(-3) = 6 ⇒ (3)

Use equation (3) to find the value of b

∵ a(0) + b(-3) = 6

∴ 0 - 3b = 6

∴ -3b = 6

- Divide both sides by -3

∴ b = -2

Substitute b in equation (1) or equation (2) to find a

∵ a(5) + b(-2) = 11

∴ 5a - 2b = 11

∵ b = 2

∴ 5a - 2(2) = 11

∴ 5a - 4 = 11

- Add 4 to both sides

∴ 5a = 15

- Divide both sides by 5

∴ a = 3

To check your answer substitute a and b in equation (2)

∵ a(-4) + b(2) = -16

∴ -4a + 2b = -16

∵ a = 3 , b = -2

∵ The left hand side is -4a + 2b = -4(3) + 2(-2) = -12 - 4 = -16

∵ The right hand side is -16

∴ L.H.S = R.H.S

∴ The values of a and b are 3 , -2

The values of a and b are a = 3 , b = -2

Learn more:

You can learn more about the equations in brainly.com/question/11306893

#LearnwithBrainly

8 0
3 years ago
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