find deri(10 points) A survey gives the value of the following variables for a sample of households in the UK: x1= number of people in the household x2= total household income x3= total household expenditure on food x4= total household expenditure on clothing x5= total household expenditure on alcohol and tobacco x6= total household expenditure on other goods write the functions which give: (a) total household income (b) total household saving (c) income per person (d) expenditure on clothing per person