Your answer would be -18m-6n-30
125 is the correct answer but you answered yourself?
The question is worded poorly, but it looks like you have a lever in equilibrium, with a force x at a distance d from the fulcrum, and a force y at a distance L - d from the fulcrum. You already have the equilibrium formula for this situation:
xd = y(L - d)
If you know x, y, and d, you can solve for the length L.
3,6,12...
this is a geometric sequence with a common ratio of 2. That means u multiply each term by 2 to find the next term.
start with 3
3 * 2 = 6
6 * 2 = 12
12 * 2 = 24...this would be ur next term
so ur answer is : multiply by 2