I need help with the first question!

Teva Sport Sandals was founded in the 1980s by a seasoned river guide, Mark Thatcher, who was tired of losing his flip-flop sandals every time he look a raft ride down the Colorado River. Thatcher knew firsthand how though -style rubber sandals doned his when be was slogging through and water He figure a thong-style sandal with a heel strap on the bacj would be the answer to keeping sandals on His new sandal creation was called the Teva (which means nature in Hebrew and it was an immediate hit with water sports enthusiasts on the river and with others nowhere near a river. Compute the spending variance and the efficiency variance for variable manufacturing overhead What do the spending and efficiency variances mean? What are possible causes? What explanation(s) should the plant manager give for the unfavorable variable overhead flexible-budget variance this month