Question

Arithmetic series/ sequence or Geometric series / sequence

Answer 1

a writer wrote 890 words on the first day, 760 words on the second day, and 630 words on the third day, and so. How many words did the write write in a week?

Answer 2

the number of words decrease by a constant amount. What is that amount?

Answer 3

I got 110, common difference is 130

Answer 4

this is an arithmetic sequence with common difference 630-760 = ?

Answer 5

\[S _{n}=\frac{ n }{ 2 }(2a+(n-1)d\]

Answer 6

Here, n=7
a=890
d=-130

Simplify and you are done :)

Answer 7

ohhh so I used the wrong formula, hold on ill simplify it

Answer 8

Doing a mistake is a part of learning :P
Okay, waiting ;)

Answer 9

isn't this the correct formula?