Mathematics
AdelaShawver37
37

Row 3 - 4 stickers Row 5 - 9 stickers Row 7 - 16 stickers How many stickers would she need to make a design with 25 rows in the same pattern? Pattern - row 3          row 5 S                    S SS                 SS S                  SSS                       SS                       S

+3
(1) Answers
NolanWineberg571

If you notice the above 2 patterns, the number of sticker in each rows forms an Arithmetic progression In 1st part it increases, and in 2nd part it decreases. so for 25 row pattern, divide it in 2 parts 1st part upto = (n+1)/2 rows = 13 2nd part = (n-1)/2 rows = 12 A.P for 1st part Sum = 13/2 (1 + 13) =91 AP for 2nd part  Sum = 12/2(12+1) = 78 Therefore total Stickers required = 91 + 78 = 169

Add answer