Correct Option: B

Let the original speed of the person be x km/hr. and the distance be y km.
Case : I

y	−	y	= 40 minutes
x		x + 3

or,	40	hr.
	60

or,	y	−	y	=	40	=	2
	x		x + 3		60		3

or,   y		1	−	1			=	1
		x		(x + 3)				3

or,   y		x + 3 − x			=	2
		x (x + 3)				3

or,	3y	=	2
	x (x + 3)		3

or,   2 x (x + 3) = 9y       ...(i)
Case : II

=	y	−	y	=	40
	x − 2		x		60

or,   y		1	+	1		+	2
		x − 2		x			3

or,   y		x − x + 2			=	2
		x (x − 2)				3

or,	2y	=	2
	x (x − 2)		3

or, x (x – 2) = 3y       ... (ii)
On dividing equation (i) by (ii) we have,

2x(x + 3)	=	9y
x (x − 2)		3y

or,	2(x + 3)	= 3
	(x − 2)

or,   2x + 6 = 3x – 6
or,   3x – 2x = 6 + 6 = 12
or,   x = 12 km/hr.
∴  Original speed of the person
= 12 km/hr.
Putting the value of x in equation (ii)
12 (12 – 2) = 3y
or,   3y = 12 × 10

or,   y =	12 × 10	= 40
	3

∴  The required distance = 40km.