Requirements 1. Calculate the variable overhead rate variance. 2. Calculate the variable overhead efficiency variance. Requirement 1. Calculate the variable overhead rate variance. Begin by determining the formula for the variable overhead rate variance, then compute the variable overhead rate variance. (Enter the variance as a positive number. Enter amounts in the formula to the nearest cent and then the variance amount to the nearest whole dollar Label the variance as favorable (F) or unfavorable (U).) Begin by determining the formula for the variable overhead efficiency variance, then compute the variable overhead efficiency variance. (Enter the variance as a positive number Enter amounts in the formula to the nearest cent and then the final variance amount to the nearest whole dollar Label the variance as favorable (F) or unfavorable (U).)