If 60 women spin 48 kg of cotton by working 8 hours daily, how much cotton will 30 women spin by working 12 hours daily? 

Solution: 
As the number of Women decrease, the cotton spin will also decrease. It is a direct proportion. 
As the working time increase, the cotton spin will also increase. It is also a direct proportion. 
Let the cotton spin be ï½˜ kg

Here the equation will be 

`\frac{ｘ}{48}`  = `\frac{12}{8}` ï½˜ `\frac{30}{60}` 

Or

ｘ = `\frac{12}{8}` ï½˜ `\frac{30}{60}`  ï½˜ 48 kg

by simplifying we get

ｘ =  36 kg

Thus, 36 kg cotton will be spin