SASMO 2013 Primary – Next Number in Sequence?

Given the sequence

 

19, (?) , 70, (??), 189

 

Find the missing terms and the pattern for this sequence

 

Solution

 

 

Observe that

 

70 – 19 = 51 = 17 x 3

 

189 – 70 = 119 = 17 x 7

 

And also that:

 

19

 

(?) = 19 + (17 x 1) = 36

 

70 = 36 + (17 x 2)

 

(??) = 70 + (17 x 3) = 121

 

189 = 121 + + (17 x 4)