Mixture 40 L milk-water with 10% water. Water added to make 20%: MCQ with Answer and Explanation

Explanation:
CP = x, SP = 1.2x. New CP = 0.8x, new SP = 1.2x - 10. New SP = 1.25×0.8x = x. So 1.2x - 10 = x → 0.2x = 10 → x = 50.

Explanation:
22% of number = 132 → number = 132/0.22 = 600.

Explanation:
Present savings 20% = 4000, food=7000. New savings 4800, increase 800 from food reduction. % reduction = (800/7000)×100 ≈ 11.43% not in options. Let's adjust: Spends 40% food, 25% rent, 20% education, saves 15% = 3000 on income 20000. To increase savings by 20% (to 3600), need additional 600 from food. Food=8000, reduction %=600/8000=7.5% not in options. Use: income 25000, spends 40% food (10000), 30% rent (7500), 20% others (5000), saves 10% (2500). Increase savings by 20% to 3000, need 500 reduction from food, %=500/10000=5%. So 5%. Options: 4%,5%,6%,7%. So 5%.