box of 100 gasket contains 10 gaskets with type A defects, 5 gaskets with type B and 2 gaskets with both types of defects. Find the probabilities that
defects
a) a gasket to he drawn has a type R defect under the condition that it has a type A defect.
b) a gasket to be drawn has no type B defect under the condition that it has no type A defect.
