Question

A monument is built out of toothpicks. There are 30 rows and each row has seven more toothpicks than the row above. The top row has five toothpicks. How many toothpicks are on the bottom row? Can someone explain how I would solve this I don't understand

Answer 1

You could write a function for the amount of toothpicks per row:
Row 1 (the top) has 5 and you add 7 each time:
t = 7(r) - 2
where t = # of toothpicks and r = row

Answer 2

why is it - 2?

Answer 3

To make row 1 have 5 toothpicks

Answer 4

so the answer is 208 toothpicks?

Answer 5

t = 7(30) - 2

Answer 6

How did you get the -2 though

Answer 7

xjai, did you give up on the other geometric series problem I was helping you with?

Answer 8

That is the answer 208

Answer 9

The 7 is the amount of toothpicks added each time and the -2 is because the first row has 5 toothpicks in it (5 - 7 = -2)

Answer 10

no the answer is

t = 5 + (r - 1)d

t = 5 + (30 - 1)7

Answer 11

well the answer is the same sorry but easier equation to work with and to understand with

Answer 12

To-MA-to, to-MAY-to

Answer 13

where

t = total number of toothpicks on last row
r = the amount of rows
d = how much more in each row

Answer 14

Ok, I was lost for a minute but the equation Lil gave made me understand it better