 
<translate> Jimlar lambobi goma sha biyu = 12X7 = 84 Jimlar lambobi 9 na farko da lambobi 2 na ƙarshe shine = 9 X 6 + 2 X 10 = 74 Lambar da ke tsakiya ita ce (84 - 74) = 10 Amsar ita ce: (B). <eng> The total of twelve numbers = 12X7 = 84
The total of first 9 and last 2 numbers is = 9 X 6+2 X 10 = 74
So, the middle number is (84 - 74 ) = 10
The answer: (B). 