A steel plate has initial thickness of 10 mm was reduced by

A steel plate has initial thickness of 10 mm was reduced by rolling process to
4 mm. Calculate the number of rolling stages if the maximum percentage of
reduction in the thickness in each stage was 20 %

Solution

No of rolling stages = 4

for first roll the thick ness is reduced by 20% that thickness reduced to 8mm

for second roll thickness is reduced by 20 % that is (8*80)/100 , so the final thickness is 6.4mm

for third rol it is reduced to 5.12 mm

for fourth roll it is reduced to 4 mm

So the total no of passes is 4