11 + 2 = 1. Prove it. How?

Soalan pertama yang ditanya dalam interview MARA 27 Mac lalu.

Rasa nak tercekik dengar soalan 'cenggitu'. Tapi terbaiklah sebab finally tiada seorang pun dapat jawab. T___T

However, the answer is soooo easy.. 

Look at the watch / your 'ding dong' at the wall.

Hope you'll find the answer. =)