Supply costs at Lattea Corporation's chain of gyms are listed below:

Client-Visits Supply Cost
March 11,661 $28,575
April 11,457 $28,409
May 11,989 $28,833
June 13,400 $28,920
July 11,721 $28,636
August 11,207 $28,235
September 12,001 $28,834
October 11,692 $28,592
November 11,840 $28,717

Management believes that supply cost is a mixed cost that depends on client-visits. Use the high-low method to estimate the variable and fixed components of this cost, Compute the variable component first, rounding off to the nearest whole cent. Then compute the fixed component, rounding off to the nearest whole dollar. Those estimates would be closest to: (Round your Variable cost per unit to 2 decimal places.)

a. $2.00 per client-visit; $28,637 per month

b. $.89 per client-visit; $17,708 per month

c. $0.35 per client-visit; $24,261 per month

d. $0.31 per client-visit; $24,766 per month

The costs can be of fixed nature or a variable nature or of a mixed nature. A mixed costs contains a component of both fixed and variable costs. The high-low method is used to calculate the variable component per unit of a mixed cost. Th formula for high low method is:

Variable cost per unit = (Highest activity cost - Lowest activity cost) / (Highest activity level - Lowest activity level)

the highest activity is in June, 13400 client visits and the highest cost is also of this activity. The lowest activity is in August, 11207 client visits and the lowest cost belongs to this activity.

Variable cost per unit = (28920 - 28235) / (13400 - 11207)

Variable cost per unit = $0.31 rounded off to two decimal places

The fixed cost = Total cost - total variable cost

Taking 13400 activity,

The fixed component is = 28920 - (0.31 * 13400) = $24766 per month

Thus, the correct answer is d.