Which number should replace both the asterisks in (* /21) x (*/189) = 1 ?  Answers:
A) 21
B) 63
C) 3969
D) 147
E) 167
Answer   Let (y/21) x (y/189) = 1   Then , y2 = 21 x 189 = 21 x 21 x 9   ∴ y = (21 x 3) = 63 .   Option: 63
<result>B</result>
Which number should replace both the asterisks in (* /21) x (*/189) = 1 ?