IMAT 2012 Q30 [Percentage]

After a long period of dry weather, the water container in my garden contained only 28% of its capacity of water. Last week’s rain, however, increased the amount of water in the container by 25%, and according to the weather forecast, a similar amount of rain is expected to fall this coming week.

If, as expected, the container gets the same amount of rainwater this coming week as it did last week, what percentage of its capacity will it then contain?

A. 66.25%
B. 42.00%
C. 78.00%
D. 60.00%
E. 43.75%

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.

To find the increase in water, we can take \frac{\text{28%}}{4}

=77%

We divide 28 by 4 to find out how much 25% of 28 is. Now we can take this answer and add it to 28% to give us the new amount of water in the water container.

28% + 7% =35%

Next, we know that we will get the same amount of rainwater next week, which is still 7% of the water barrel’s total.

35% + 7% = 42%

\fcolorbox{red}{grey!30}{Therefore the answer is B, $42$%}