Two spring having stiffness constants of 22N/mm and 25N/mm are connected in parallel. They are to be replaced by a single spring to have same effect. The stiffness of that spring will be?

Two spring having stiffness constants of 22N/mm and 25N/mm are connect

1.	Two spring having stiffness constants of 22N/mm and 25N/mm are connected in parallel. They are to be replaced by a single spring to have same effect. The stiffness of that spring will be?
A.	None of the mentioned.
B.	3N/mm
C.	47N/mm
D.	11.7N/mm
Answer» D. 11.7N/mm