The equation r=-0.0028t+20.8 can be used to predict the world record in the 200-m dash, where r is the record in seconds and t is the number of years since 1920. in what year will the record be 18.0 seconds?

The world record for the 200-m dash will be set at 18.0 seconds in the year 2920.

Step-by-step explanation:

To find what year the record will be 18 seconds, substitute 18 in for R, and solve for t.

-0.0028t + 20.8 = R

-0.0028t + 20.8 = 18

-0.0028t = -2.8

t = 1000

The record for the 200-m dash will be 18 seconds after 1000 years. To find which year this record will be set in, add 1000 to the original date, 1920.

1920 + 1000 = 2920

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