Step 1: We make the assumption that 125 is 100% since it is our output value.
Step 2: We next represent the value we seek with $x$x.
Step 3: From step 1, it follows that $100\%=125$100%=125.
Step 4: In the same vein, $x\%=40$x%=40.
Step 5: This gives us a pair of simple equations:
$100\%=125(1)$100%=125(1).
$x\%=40(2)$x%=40(2).
Step 6: By simply dividing equation 1 by equation 2 and taking note of the fact that both the LHS (left hand side) of both equations have the same unit (%); we have
You take the percent and move the decimal two places to the left. In this case the percent is 40 so the decimal would be on the right of the 0 (40.0%) So that would make it .40 then multiply .40 x 125. Hope this helps.
Assuming no cubes are hidden from view, the base view (as if you're looking from underneath the figure) would have a 2 x 2 square of cubes, plus one at the top. This means that your correct choice would be the one I've attached.