Помогите решить задачу по экономике предприятия!

Problem 1 Result of technological improvements was defined by decreasing of a norm of time input for a one product on 22 % and by increasing of an output of qualitative products from 72 % up to 76%. Calculate a change of productivity through economy of materials, in %.
The initial data:
Direct material expenses for a product, grn18,2
Norm of time input for a product, norm - hours5,0
The average rank of worker (bad condition)4
The average value of bonus, %25,0
Additional wages, %12,0
Social insurance, % 38
Common manufacturing expenses for a product, grn17,7