Calc
posted by Chris .
A video games shop is analyzing its sales performance using matrices. Matrix A contains the unit sales data for each product category (horizontally) per week (vertically). Matrix B contains the unit sales data for weekends for each category (horizontally) per week (vertically). To find out how many games in each product category were sold each week only during weekdays, which matrix operation must be performed?
A.
Add matrix A to the inverse of matrix B.
B.
Add matrix A to the inverse of matrix A and then subtract it from matrix B.
C.
More data is needed to calculate the sales during weekdays.
D.
Subtract matrix B from matrix A.
E.
Add matrix A to matrix B.

Looks like (D) to me.
Subtract weekend sales from week total to get weekdayonly sales.