The cost of item A is 8 more than the sum of cost of B and

Solution

Let the cost of item B and C be 3x and 5x respectively.
Since, the cost of B i.e. 3x is a multiple of 8 and is less than 90.
Cost of B = ₹24 or ₹48 or ₹72
Case I:
When the cost of B = ₹24
Cost of item C = 24*5/3 = ₹40 (which is less than 50)
Case II:
When the cost of B = ₹48
Cost of item C = 48*5/3 = ₹80 (which is between 50 and 100)
Cost of item A = 80 + 48 + 8 = ₹136
P = sum of cost of A and B together = 136 + 48 = ₹184
Case III:
When the cost of B = ₹72
Cost of item C = 72*5/3 = ₹120 (which is more than 100)
Cost of item A = 72 + 120 + 8 = ₹200
Q = difference between the cost of A and C = 200 - 120 = 80
I: (P - Q) = 184 - 80 - 4 = 100 is a square number.
II: Sum of P and Q = 184 + 80 = 264 is equal to 264.
III: (3Q - P) = 3*80 - 184 = 56 is a multiple of 14.