Distance between Smith's house and office is D km. On Monday, Smith tr

Distance between Smith's house and office is D km. On Monday, Smith traveled to his office at M km/hr for the first 20 km, and the rest at a speed of 1.25M km/hr. On, Tuesday, Smith traveled the same distance at a speed of M km/hr. what is ratio of time taken by Smith to travel from his house to office on Monday and Tuesday?
For Monday:
Time taken Tm = \((\frac{20}{M} + \frac{D-20}{1.25M})\) Hours
For Tuesday Tt = \(\frac{D}{M}\)
Now,
\(\frac{Tm}{Tt} = (\frac{20}{M} +\frac{D-20}{1.25M})/{\frac{D}{M}}\) = ?
\(\frac{Tm}{Tt} = \frac{20}{D} +(\frac{D-20}{1.25})*\frac{1}{D}\) = ?

Hence D =?

(1) \(M = 48\)
Clearly, INSUFFICIENT.

(2) \(D = 40\)

SUFFICIENT.

Answer B.