how many girls like sports? well, what's 2/5 of 1200? well, is just their product, 2/5 * 1200.
how many boys like sports? well, what's 3/5 of 1200? 3/5 * 1200.
[tex]\bf \cfrac{2}{5}\cdot 1200\implies \cfrac{2\cdot 1200}{5}\implies \cfrac{2400}{5}\implies \stackrel{girls}{480}
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\cfrac{3}{5}\cdot 1200\implies \cfrac{3\cdot 1200}{5}\implies \cfrac{3600}{5}\implies \stackrel{boys}{720}
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\textit{how many }\stackrel{students}{pupils}\textit{ like sports?}\qquad 480 + 720[/tex]
