Solution :
a). Flexible budget
A flexible budget is a budget that is prepared for the different volume level which was originally anticipated.
b). Flexible budget variance
It is the different between the flexible budget and the actual results.
c). Return on Investment
It is used to evaluate the performance of the investment centers. It is calculated by dividing operating income by the investment.
d). Favorable variance
The company has the favorable variance when the actual values are more than the budgeted values.