The water bill solution By Eugene Gofenshefer from Latvia
a ) If I didn ’ t consume a single cubic meter of water I still have to pay 0.3128 €, as x ∈ [ 0 ; 35 ] b ) 23≤35 , therefore 23x0.3128 = 7.1944 c ) 35≤40 < 50 , therefore 35x0.3128 + 5x0.8462 = 15.17 d ) 53≥50 , therefore 35x0.3128 + 15x0.8462 + 3x1.4462 = 27.9796 .
e ) 54.94 €> 27.98 €, therefore x≥50 , so 35x0.3128 + 15x0.8462 + 1.4462x = 54.94 € from which we get that x≈21.64 cubic meters .
f ) A piecewise-defined function ( y asis – price , x asis – amount of cubic meters )