question_answer

Two non-intersecting circles, one lying inside another, are of radii a and b (a > b). The minimum distance between their circumference is c. The distance between their centres is

A) a - b

B) a - b + c

C) a + b - c

D) a - b - c

Correct Answer: D

Solution :

 Let A and B be the centres of two circles. Here \[AD=a,\,\,BC=b\] and \[CD=c.\] \[AB=AD-(BC+CD)\] \[=a-(b+c)=a-b-c\]