Answer: C
Let the volume of sphere P be 64 parts.
Therefore volume of sphere Q = 64 - (37/64)% of 64 = 64 - 37 = 27 parts.
The volume of R = 27 - (19/27)*27 = 27-19 = 8 parts.
Volume ratio =P:Q:R = 64:27:8
Radius ratio = P:Q:R = 4:3:2
The surface area will be 16:9:5
Surface area of R is less than the surface area of sphere P
16k - 4k = 12k
Now, 12k/16k * 100 = 75%
Thus surface area of sphere R is less than the surface area of sphere P by 75%.

Answer: A
Let the marks scored by P,Q,R and S be a, ak, ak² and ak³ respectively.
Marks scored by R were 275/9% less than the marks scored by P and Q.
So, if marks scored by P and Q were 36 then those scored by R is 25.
Marks scored by P and Q = a+ak =36
Marks scored by R = ak² =25
=> (a+ak)/ak² = 36/25 => k= 5/4.
P =a, Q = 5a/4, R= 25a/16, S = 125a/64
=> P= 64a, Q = 80 a, R = 100a and S = 125a
S scored (125a-80)/80a * 100 more than Q
=> (45/80) * 100 = 56.25%
S scored 56.25% more than Q..