He has has ten patterns of chairs and eight patterns of tables
Hence, A chair can be arranged in 10 ways and
A table can be arranged in 7 ways
Hence one chair and one table can be arranged in 10 x 7 ways = 70 ways
An design manager has 10patterns of chairs & 7patterns of tables. In how many ways can he make a pair of table & chair?
  70
  40
  80
  90
  100