While training for a marathon, jeff wants to increase the number of miles he runs each day. on the first day of training, jeff runs 5 miles. he plans on increasing the number of miles he runs a day by 1 for the remainder of the week. write a series to model the situation.

also the series doesn't have to be more than seven numbers

The series is 5 , 6 , 7 , 8 , 9 , 10 , 11

Step-by-step explanation:

* Lets revise the arithmetic series

- In the arithmetic series there is a constant difference between

 each two consecutive numbers

- Ex:

# 2  ,  5  ,  8  ,  11  ,  ……………………….  (constant difference is 3)

# 5  ,  10  ,  15  ,  20  ,  …………………………  (constant difference is 5)

# 12  ,  10  ,  8  ,  6  ,  ……………………………  (constant difference is -2)

* General term (nth term) of an Arithmetic series:

- If the first term is a and the common diffidence is d, then

 U1 = a  ,  U2  = a + d  ,  U3  = a + 2d  ,  U4 = a + 3d  ,  U5 = a + 4d

- So the nth term is Un = a + (n – 1)d, where n is the position of the

 number in the series

* Lets solve the problem

- Jeff wants to increase the number of miles he runs each day

∴ He will add the initial value by constant number each day

- He plans on increasing the number of miles he runs a day by 1

∴ The constant value is 1 mile

-  On the first day of training, Jeff runs 5 miles

∴ The first value is 5 miles

∴ The series is arithmetic

∵ a = 5 , d = 1

- He do that for the remainder of the week

∵ The week has 7 days

∴ The series has 7 terms

∵ The rule of the series is Un = a + (n - 1)d

∵ a = 5 and d = 1

∴ Un = 5 + (n - 1)(1)

∴ Un = 5 + n - 1

∴ Un = 4 + n ⇒ n is the position of the number

- Substitute n from 1 to 7 to find the series

∴ The series is 5 , 6 , 7 , 8 , 9 , 10 , 11

72 is the answer to this problem

$5.41

step-by-step explanation:

$20 - $14.51 = $5.49.