IMAT 2012 Q28 [Marbles]

Three friends, Adam, David and Sue are sharing out a bag of marbles. To do this more quickly, they take 10 marbles each time and repeat until the bag is empty. There are not enough marbles for Sue to take 10 on the last turn. Adam and David then give her two marbles each and they all have the same.

How many marbles did Sue take on the last turn?

A. 4
B. 2
C. 8
D. 6
E. 3

Simple steps to solve word problems:

  • Underline key information
  • Determine what they are trying to ask, and what you will need to solve it
    Eliminate any non-essential information
  • Draw a picture, graph, or equation
    In moments of high stress like exam taking, always work with the paper they give you to avoid careless mistakes.
  • Solve.


10 - 2 = 8


10 - 2 = 8

So they both have 8 marbles. It says that at the end, they all have the same.

Sue at the end has 8 marbles. This is after both Adam and David gave her 2 each. Then we can say that her total on the last turn = 8 - 2 - 2 = 4

Therefore she must have taken 4 marbles on the last turn.

\fcolorbox{red}{grey!30}{Therefore A is the answer}