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dalvyx [7]
2 years ago
11

If a person rows to his favorite fishing spot 21 miles downstream in the same amount of time that he rows 7 miles

Mathematics
1 answer:
klio [65]2 years ago
8 0

28 miles upstream requires 28/7 = 4 hours.

28 miles downstream requires 28/21 = 4/3 hours, or 1 hour and 20 minutes.

How long does it take him to cover 28 miles?

Apply the distance formula:

d = rt

where

d is distance

r is rate or speed

t is time

21 = t*(r+7)  = rt+ 7t

7 = t *(r-7)   = rt - 7t

            28 = 2rt

             14 = rt

             21 = rt + 7t

             21 = 14 + 7t

               7 = 7t

                 t=1

              21 = (r+7)*1 = r+7

                r = 14

The speed of the boat is 14 mph. With the current (downstream), the speed is 14+7 = 21 mph, so 21 miles are traveled in 1 hour. Against the current (upstream), the speed is 14-7 = 7 mph, which means 7 miles are traveled in the same 1-hour time frame.

28 miles downstream requires 28/21 = 4/3 hours, or 1 hour and 20 minutes.

28 miles upstream requires 28/7 = 4 hours.

To learn more about sequences refer to:

brainly.com/question/340538

#SPJ9

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Lapatulllka [165]

Answer:

12 hours

Step-by-step explanation:

Given data

Steve= 4 hours

Steve and Andrea= 3 hours

Applying the combined work formula

1/A+1/B= 1/T

1/4+1/B= 1/3

solve for B

B+4/4B= 1/3

cross multiply

3(B+4)= 4B

3B+12= 4B

12= 4B-3B

12= B

Hence Andrea will spend 12 hours alone

6 0
3 years ago
X+3y=6 Solve for x and y
seropon [69]

Answer:

x=(6,0)

y=(0,2)

or

x=6-3y

y=2-x/3

Step-by-step explanation:

6 0
2 years ago
Read 2 more answers
Analyze both functions and describe in detail under what conditions Stephanie's profit, in dollars, would be greater than Bryson
fomenos

Answer:

The number of tomatoes must be less than 40.

Step-by-step explanation:

Stephanie and Bryson both grow tomatoes to sell at farmers' markets. Stephanie grew a total of 70 pounds  of tomatoes to sell. She plans to sell the tomatoes for $3.50 per pound. The equation below represents the  profit in dollars, f(x), she will earn by selling x pounds of the tomatoes.

f(x) = 3.50x -110

Bryson plans to sell his tomatoes at a different farmers' market. He grew a total of 90 pounds of tomatoes.

The table below shows the profit, in dollars, he will earn by selling different numbers of pounds of

tomatoes.

Bryson's Tomato Sales

-97.50 -55.00 -12.50 30,00

Profit (dollars)

Pounds of

Tomatoes Sold

10

20

30

40

Solution:

For Stephanie, let x represent the number tomatoes sold and f(x) represent the profit in dollars. The profit is given by:

f(x) = 3.5x - 110

For Bryson, let x represent the number tomatoes sold and y represent the profit in dollars. From the table, the profit can be represented by the points (10, -97.5) and (40, 30). The profit can be gotten using the formula:

y-y_1=\frac{y_2-y_1}{x_2-x_1} (x-x_1)\\\\y-(-97.5)=\frac{30-(-97.5)}{40-10} (x-10)\\\\y+ 97.5=4.25(x-10)\\\\y+97.5=4.25x-42.5\\\\y=4.25x-140

Stephanie profit > Bryson profit

3.5x - 110 > 4.25x - 140

3.5x - 4.25x > -140 + 110

-0.75x > -30

x < 40

8 0
3 years ago
Help plz no links will mark brainliest if correct!
BARSIC [14]

Answer:

8

Step-by-step explanation:

Because when you add them you get 2m+8/2m

Which is equal to 8/1 or 8

6 0
3 years ago
Read 2 more answers
Will mark brainliest im in a rush so please help me if you can
Afina-wow [57]

Answer:

B!

Step-by-step explanation:

5 0
2 years ago
Read 2 more answers
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