Friends, I have a problem, understanding Question 27,28 (Chapter 3: Averages LOD III). Here question asks to find minimum possible value of B's Average. Having solved the previous problems, my logic entails following operations:
1. Our first priority is to maximize C, therefore maximum of sum of 5 (A,B) i.e. max(110,155)=155 shall be transferred from B to C and minimum sum value from C i.e. min(130,165)=130 should be taken off from C. Subsequently, C's max. average is given by (900-130+155)/30.
2. Now, in order to minimize the value of B we must take off maximum from B and transfer back minimum amount to B. Since, 155 is taken off already to maximize C now, I assume that C gives 130 to A and for B's loss of sum for transferring 155 to C, A gives it's minimum i.e. 90 to B. Making min. average of B as (625-155+110)/25=25-65/25=25-2.6=22.4. Here answer given is option (c) i.e. 22.6.
3. Consequently, my answer is wrong for question 28 as well. (I hope it's due to my thought process in previous question.)
I'll really appreciate if any one explains the right approach or points out my mistake.