Answer:
Reduction in work in progress = $7500
Explanation:
given data 
time = 10 hours 
time = 15 hours 
worth  = $1,500
to find out
reduction in work in process value
solution
we find work in progress   by this formula 
work in progress  = Flow rate  × Cycle Time     .......................1
so Initial work in progress is 
Initial work in progress   = (1 per hour)  × 10 hours = 10
and Final work in progress is here 
Final work in progress   = (1 per hour) × 15 hours = 15
so 
Initial work in progress   value = 10  × 1500 
Initial work in progress   value= $15000
and
Final work in progress    value =15  × 1500 
Final work in progress    value = $22500
so 
Reduction in work in progress = $22500 - $15000 
Reduction in work in progress = $7500