It would take him 12 days.
1/3 x 3 = 3
3x4=12
We'll do the first one. I can't read the variable, but it looks like a

so that's what I'll use, but it doesn't matter.
First, get the variable by itself:

You get that before you multiply each side by two.
Now, you color the line so that all values that are less than 6 are shaded, so you put an open circle at 6 since it's not included and then you shade everything to the left.
97 is the answer to your question
1/6^3 is also equivalent to 6^-3. It can be reverted back to 1/216. Answers on ed2020 are A. and D.