Question

please help:))

Answer 1

@jim_thompson5910 :) ha another, you seem to be really helping me today!

Answer 2

what do you have so far?

Answer 3

i though n was 1, d was 3, and an was 60 and the final answer was 119 but i was wrong

Answer 4

the sequence of pennies goes like this: 1, 3, 5, 7, 9, ...

Answer 5

what pattern is happening here?

Answer 6

plus 2

Answer 7

yes

Answer 8

so d = 2

Answer 9

we'll use n = 60 because there are 60 terms here (from day 1 to day 60)

Answer 10

okay

Answer 11

Now we plug a1 = 1, d = 2 and n = 60 into the formula below to get...
\[\Large a_n = a_1 + d(n-1)\]
\[\Large a_n = 1 + 2(n-1)\]
\[\Large a_n = 1 + 2(60-1)\]
\[\Large a_n = ???\]

Answer 12

177?

Answer 13

no

Answer 14

you need to follow PEMDAS

Answer 15

you do NOT do 3*59 = 177

Answer 16

oops 119

Answer 17

yes 119

Answer 18

so
day 1 = 1 penny
day 2 = 3 pennies
day 3 = 5 pennies
day 4 = 7 pennies
...
...
...
...
day 60 = 119 pennies

Answer 19

so an and the final is both 119

Answer 20

now we use this formula
\[\Large S = \frac{n*(a_1+a_n)}{2}\]
plug in the values to get
\[\Large S = \frac{60*(1+119)}{2}\]
\[\Large S = ???\]

Answer 21

3600

Answer 22

so....
n = 60
d = 2
a_n = 119 (when n = 60)
S = 3600

see attached

Answer 23

thank you

Answer 24

be careful to type `3600` and not `3,600` otherwise the computer will think you're typing in 2 different values

Answer 25

np