Domino towers

This task is about completing a pattern and writing a rule to describe the pattern.
Courtney built towers of different heights out of dominoes.
 
The 1-storey-high tower used 3 dominoes.
1-storey-high tower used 3 dominoes
The 2-storey-high tower used 8 dominoes.
2-storey-high tower used 8 dominoes
The 3-storey-high tower used 15 dominoes.
3-storey-high tower used 15 dominoes

Question 2Change answer

a)  Complete this table.
Storeys High (s)   1   2   3   4   5   6  
Number of Dominoes (n)   3   8   15  

Question 2Change answer

b)  Write an equation describing the number of dominoes, 'n', needed to build a tower 's' storeys high.
n =

Question 2Change answer

c)  How many dominoes does Courtney need to build a tower 98 storeys high?