quick

[skillszone]

<FONT color=#ff0000>X</FONT> is now being sold at $ 20 a kg. During last month its rate was $ 16 per kg. By how much percent should a family reduce its consumption so as to keep the expenditure fixed?

[Fibonacci]

suppose they used 10kg

at $16 per kilo costs 16 x10 = 160

to keep costs unchanged they need to reduce consumption to
160 / 20 = 8kg

a reduction of 20%