`(s:48)-(s:50)=20`
`<=>s/48-s/50=20`
`<=>(25s)/1200-(24s)/1200=20`
`<=>s/1200=20`
`<=>s=24000`
Vậy `s=24000`
\(\dfrac{S}{48}-\dfrac{S}{50}=20\)
\(\Leftrightarrow\dfrac{50S-48S}{48\cdot50}=20\)
\(\Leftrightarrow2S=48\cdot50\cdot20=48000\)
\(\Leftrightarrow S=24000\)
\(\dfrac{s}{48}-\dfrac{s}{50}=20\)
\(\Leftrightarrow\dfrac{25s}{1200}-\dfrac{24s}{1200}=\dfrac{24000}{1200}\)
\(\Rightarrow s=24000\)