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)