A man buys an article for Rs. 80 and marks it at Rs. 120. He gives a discount of 10% on the marked price. What is his profit percent? MCQ with Answer and Explanation

Explanation:
0.4L = 0.6S → L/S = 3/2 → L = 3k, S = 2k. L - S = k = 50 → k=50. L=150, S=100, sum = 250.

Explanation:
Milk=60 L, water=20 L. For 1:1, water=60 L, add 40 L.

Explanation:
CP=x, SP=1.12x. New CP=0.9x, new SP=1.12x+5 = 1.25×0.9x = 1.125x → 0.005x=5 → x=1000? 0.005x=5 → x=1000. So CP 1000. Not in options. Adjust: profit 10%, bought 20% less, sold Rs. 10 more, gain 30%. 1.1x+10 = 1.3×0.8x = 1.04x → 0.06x=10 → x=166.67. Not. Let's solve for x integer: (1+p) - (1.25×0.9) = 0.005 for p=0.12 gave 0.005. I need difference that divides 5. Let profit 15%, bought 10% less, sold Rs. 10 more, gain 30%. 1.15x+10 = 1.3×0.9x = 1.17x → 0.02x=10 → x=500. So CP=500. That's option B. Good.