Rs. 20 is the true discount on Rs. 260 due after a certain time. What will be the true discount on the same sum due after half of the former time, the rate of interest being the same?

A. 360 cc
B. 60 cc
C. 300 cc
D. 36 cc
r1 = x  r2 = 3x
Π * x2 * h = 40
Π9 x2h = 40 * 9 = 360

A. 90, 85, 60
B. 85, 75, 60
C. 90, 75, 70
D. 90, 75,60
Explanation:
Length = 6x
Breadth = 5x
Height = 4x in cm
Therefore, 2(6x × 5x + 5x × 4x + 6x × 4x) = 33300
148×2 = 33300
=> x2 = 33300/148 = 225
=> x = 15.
Therefore, Length = 90cm,
Breadth = 75cm,
Height = 60cm
90, 75 , 60 cm