Below is a worked through solution of a Lantite style question that has been asked of me.
Question
Year 5 are deciding what story to read during a wet weather lunch. 1/3 of the class voted for Storm Boy. 2/5 are avid Harry Potter fans and voted for The Philosophers Stone. The remaining 8 students voted for The Demon Headmaster. What fraction voted for the Demon Headmaster?
Answer
One way you can do it through fractions. Find a common denominator through multiplication.
1/3 = Storm Boy fans
2/5 = Harry Potter fans
A common denominator is 15.
1/3 is equivalent to saying 5/15 (whatever you times the denominator by you times the numerator by) and 2/5 is equivalent to 6/15.
then when you add 5/15 and 6/15 = 11/15.
The whole of any fraction is 1 or in this case 15/15.
So The Demon Headmaster fans must be the whole or 15/15 minus 11/15 (the combination of Storm Boy and Harry Potter fans) = 4/15
Extension
What book got the most votes?
- Harry Potter (surprise!) because it has 6/15 votes.
How many students were in the year 5 class?
We have just worked out that 4/15 of the students were The Demon Headmaster fans. And remember at the beginning we were told 8 students were The Demon Headmaster fans. So 4/15 = 8 students. You can work out the UNIT FRACTION OR 1/15 by dividing 8 by 4. This means 1/15 is 2 students. Then we can work out the total of students as follows:
Storm Boy fans = 5/15 = 5 x 2 = 10 students.
Harry Potter fans = 6/15 = 6 x 2 = 12 students.
The Demon Headmaster fans = 4/15 = 4 x 2 = 8 students (we’ve been told this).
Check calculations
m = 10+12+8 = 30
