type k question

[999 mum]

Hi,

This question has me stumped please help.

(1 [9] 17) (15 [14] 8 ) (4 [?]21)

options are

22, 14, 28, 44, 16

and the answer is 16.

[Sally-Anne]

Add the first and third numbers then take away 9. Tricky because the first set looks as though it is simply add both then divide by 2.

[999 mum]

Thank you, it had me totally stumped but now that you have explained it, it sounds so simple.