Klinkhammer Corporation estimated overhead for the year as follows: fixed = $720,000; variable = $4 per unit. Klinkhammer expected to produce 72,000 units for the year.

a. Compute the rate that will be used to apply overhead costs to products.
b. During the year, Klinkhammer incurred actual overhead costs of $1,104,000 and produced 74,400 units. Compute the overhead applied to units produced.
c. Compute the amount of under- or overapplied overhead and the spending and volume variances.
d. What caused applied overhead to be different from budgeted overhead?