Answer:
6
Step-by-step explanation:
Total number of subsets is given as

But the subset of a set consists of the proper subsets, an empty set and the set itself.
Total number of subsets are 64
Therefore,


Comparing both sides

The answer is 15. 37 plus 18 equals to 55 and 22 plus 18 equals to 40. 55 minus 40 equals to 15.
Given that
The cost of 1 m ribbon = Rs.75
The cost of 7/5 m ribbon
→ (7/5)×75
→ (7×75)/5
→7×15
→₹ 105
The cost of 7/5 m ribbon is ₹105.