N12 M9 X6 ,
GHD Purple Gift Set
average transaction price : = AMOUNT/V/100;
ROC: ( closing cost -REF ( mean transaction price ,
GHD Midnight Gift Set 2011, N)) / REF ( mean transaction price ,
GHD Purple Straighteners, N) * 100;
ROCMA: MA (ROC,
GHD MK4 Kiss Straighteners, M);
ROCEMA: (2 * ROC + (X-1) * REF (ROC,
GHD Blue Straighteners, 1)) / (X +1);