Question

As part of a competition a whole school years of 420 pupils were asked to write an essay. They could choose from 3 general topics that were: Science, English and a story. If `1/3` of them chose Science and `1/6` chose English how many chose story?

Answer 1

`210`

Explanation:

`color(blue)("Method 1")`

Science `->1/3xx420 = 140`
English `->1/6xx420=70`

Story `=420-140-70 = 210`
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`color(blue)("Method 2")`

Not story proportion `=1/3+1/6" " =" " 2/6+1/6" " =" " 3/6" "=" "1/2`

So story `->(1-1/2)xx420" " =" " 1/2xx420" "=" "210`