Question

In figure 1, left-hand side (LHS) and the right-hand side (RHS) of the weighing machine are equal to each other. If we add 2 on the RHS, as shown in figure 2, what should we do to equalise LHS and RHS again?

• A. Subtract 2 from LHS
• B. Add 5 to RHS
• C. Subtract 5 from RHS
• D. Add 2 to the LHS

Answer 1

The correct option is D

Add 2 to the LHS

When the weighing machine was balanced, LHS = RHS

⇒13x + 5 = 31

RHS = 31 + 2 = 33

If 2 is added to the RHS of the weighing machine, we can add 2 to the LHS of the machine to balance both the sides.

Then LHS = (13x + 5) + 2 = 13x + 7

Let us see what happens.

Aha! The machine is balanced again.