Question

we make a sequence of figures with tiles. The first four figures have 1,4,7 and 10 tiles, respectively. How many tiles will the 15th figure have?

Answer 1

43

Explanation:

1 , 4 , 7 , 10

→ Find the difference between each term

4 - 1 = 3, 7 - 4 = 3 and 10 - 7 = 3

→ Put this into the nth term format

3n + x

→ Write the 3 times tables above the sequence and find what you need to take away from the times tables to get to the sequence

3 , 6 , 9 , 12

1 , 4 , 7 , 10

→ Minus 2

3n - 2

→ Substitute 15 as n

3 × 15 - 2 = 43