Answer: Y = $4.50AH + $700,000.
Step-by-step explanation:
Based on the options given, I believe you meant that the fixed cost is 700000 and not 720000.
Note that the variable cost per activity hour will be:
= 180000/40000
= 4.50 per AH
Fixed Cost = $700,000
Therefore, using Moung's flexible-budget formula, this will be:
Y = bx + a
Y = $4.50 AH + $700,000