Find the SS and mean of 12, 11,10,9,8 7,6,5 and 8,7,6,5,4,3,2,1​

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post

Ithink the answer is b i hope it my friend message me if i’m wrong and i’ll change my answer and fix it for you