A vendor sells shirts at ₹500 each, earning a 2% commission, and ties at ₹150 each, with a 12% commission. If he sells 3 shirts and 4 ties per day, what will be his total commission earned in 30 days?

Correct — C. Find the commission on one item, then on one day, then on 30 days.

Per shirt: 2% of ₹500 = ₹10
Per tie: 12% of ₹150 = ₹18

One day: 3 × ₹10 + 4 × ₹18 = ₹30 + ₹72 = ₹102
30 days: ₹102 × 30 = ₹3060 → option (c)

Why the others are wrong

• (a)
  ₹2850 — ₹2850 ÷ 30 = ₹95 a day, ₹7 short of the true daily commission of ₹102 (₹30 from shirts plus ₹72 from ties).
• (b)
  ₹3000 — ₹3000 is ₹100 a day. The daily commission is ₹102, so 30 days earn ₹60 more than this.
• (d)
  ₹3200 — ₹3200 ÷ 30 = ₹106.67 a day — not even a whole rupee amount, although each shirt earns exactly ₹10 and each tie exactly ₹18.

Here the commission is a percentage of the selling price of each item sold. It is earned item by item, so the clean route is per item → per day → per period.

The two rates apply to different prices, so they cannot be merged into one rate. Work out each product's commission and add the rupee amounts, not the percentages.

Daily sales give the same total: 2% of ₹1500 (shirts) + 12% of ₹600 (ties) = ₹30 + ₹72.

Key facts

• Commission = commission rate × value sold.
• Rates on different prices are combined as rupee amounts, never as percentages.
• A fixed daily amount over n days totals daily amount × n.

Common traps

• Adding the rates (2% + 12% = 14%) and applying 14% to one price, although the rates belong to different prices.
• Leaving out the quantities: ₹10 + ₹18 = ₹28 counts one shirt and one tie, not 3 shirts and 4 ties.
• Stopping at one day's ₹102 without the 30-day multiplier.

No directly related past PYQ was found.