Question

Once I had been to the post office to buy five-rupee, two-rupee and one-rupee stamps. I paid the clerk Rs. 20, and since he had no change, he gave me three more one-rupee stamps. If the number of stamps of each type that I had ordered initially was more than one, what was the total number of stamps that I bought?

• A. 10
• B. 11
• C. 13
• D. 14

Hint:

Try values manually for integer-constrained word problems; check total and conditions.

Answer 1

The Correct Option is C

Step 1: Let the number of five-rupee stamps = x, two-rupee = y, one-rupee = z
Step 2: Initial cost of stamps = 5x + 2y + 1z = Rs. 20
Step 3: Since clerk had no change, he gave 3 extra one-rupee stamps: total stamps = x + y + z + 3
Step 4: We are told x, y, z>1
Step 5: Try x = 2, y = 2, z = 6 → Cost = 5×2 + 2×2 + 6 = 10 + 4 + 6 = Rs. 20 ✔️
Step 6: Total number of stamps = 2 + 2 + 6 = 10
Step 7: Add the 3 extra stamps = 10 + 3 = 13 stamps