it was given that "The ending work in process inventory consists of 9,500 units. The ending work in process inventory is 100% complete with respect to materials"
it was given that "The cost per equivalent unit is $3.75 for material"
these two facts mean that the material cost of the in process inventory is 9500 x 3.75 = $35,625
subtracting that number from $41,625 will give us the dollar value of the conversion costs = $6,000
it was given that "The cost per equivalent unit is $1.25 for conversion cost"; thus $6,000 ÷ 1.25 = number of units = 4,800
4800 ÷ 9500 ≅ 51%