Hello, I was wondering if you could help me with a question? Yesterday my daughter came to me and asked if I could help her solve these three problems.
  1. 18 percent of 25 is what?

  2. 18 percent is what of 25?

  3. 25 is what percent of 18?
The only way I could think of to figure this out was with the calculator and doing 18 x 25 %= 4.5 is this the answer for all three questions?

Thanks for helping me out.

Hi Pete

First, I would say that using percent in the age of calculators is bit of 'abacus arithmatic'. I know it is still in the curiculum and in lots of vocabulary, but really is just an extra burden on the real issues. [I was struck by this, again, the last time I did my taxes ; ( ]

18% = 18/100 = 0.18

The WHAT is the variable in an algebra question - so you may have to write something, change the appearance then use the calculator.

  1. 0.18 x 25 = [What]?
    Yes [What] = 4.5.

  2. 0.18 x [What] = 25?
    That means [What] = 25 / 0.18
    - a different calculation and a different answer.

  3. 25 = [What] x 18 / 100?
    [What] = 25 x 100 / 18.
    - different again.
Hope this makes 'sense' of what they expected. Not to be confused with - these were sensible questions!!

Walter Whiteley

 

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