Justin's boat travels 175 km downstream in 5 hours and it travels 189 km upstream in 7 hours. Find the speed of the boat in still water and the speed of the stream's current.

(V + W) * 5 = 175     boat traveling downstream

(V - W) * 7 = 189       boat traveling upstream

V + W = 35

V - W = 27

2 V = 62    

V = 31 = speed of boat

2 W = 8

W = 4    speed of water

Upstream  7 * (31 - 4) = 189

Downstream 5 * (31 + 4) = 175

answer:

payment just for service  

→

$

87.12

payment for service including tax

→

$

94.09

explanation:

service only with 20% tip  

→

$

72.6

(

1

+

20

100

)

=

$

87.12

in the opening of the question the word 'service' is associated only with the pretax value.

the closing part of the question asks: how much did she pay for the  

service

−−−−−−  

so technically the answer is  

→

$

72.6

(

1

+

20

100

)

=

$

87.12

however, the intention of the question provider may have been that your answer is to be  

$

87.12

(

1

+

8

100

)

=

$

94.09

to 2 decimal places.

'

payment just for service  

→

$

87.12

payment for service including tax

→

$

94.09

tony b

mar 21, 2017

answer:

trying to explain it another way

explanation:

service charge  

.

→

$

72.60

20% tip  

20

100

×

$

72.60

=

$

14.52

−−−−−−  

←

add

$

87.12

tax  

8

100

×

$

87.12

=

$

6.97

−−−−−  

←

add

$

94.09

related questions

14

step-by-step explanation: