Question

Each student in Mrs. Henderson's science class brought in 3 books for the book donation. If there are 25 students in the class, how many total books did they collect?

Answer 1

Slightly different approach using ratio

75

Explanation:

Using ratio but in fractional format.

`color(brown)("Initial condition")`

`("book count")/("Student count") -> 3/1`

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`color(brown)("Solving the question")`

`("book count")/("Student count") -> 3/1 -=("book count")/25`

The `-=` means 'equivalent to'

To change the 1 from `3/1` into 25 multiply by 25.
To maintain proportionality of the ratio what you do to the bottom you also do to the top (for multiply or divide).

`("book count")/("Student count") -> 3/1 -=(color(magenta)(3xx25))/(1xx25)=("book count")/25`

`color(magenta)("You can now see where the method use by the others comes from")`

Total count of books `=3xx25 = 75`
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`color(blue)("Foot note")`

Multiply by 1 and you do not change the value. However 1 comes in many forms so you can change the way a number or fraction looks without changing its actual value.

`color(green)(3/1color(red)(xx1))" "->" "color(green)(3/1color(red)(xx25/25)) = 75/25`