Percentage MCQs

Explanation:
CP=x, SP=1.1x. New CP=0.8x, new SP=1.1x-12 = 1.3×0.8x = 1.04x → 0.06x=12 → x=200.

Explanation:
Let parts x, y. 0.4x - 0.3y = 20 → 4x - 3y = 200. 0.5y - 0.25x = 25 → 20y - 10x = 1000 → 2y - x = 100. Solve: x = 2y - 100. Substitute: 4(2y-100)-3y=200 → 8y-400-3y=200 → 5y=600 → y=120, x=140, sum=260.

Explanation:
Value 2 yrs ago = 216750 / (0.85×0.85) = 216750/0.7225 = 300000.

Explanation:
Multiplier = 1.1 × 0.9 × 1.2 = 1.188. Initial = 23760/1.188 = 20000.

Explanation:
Let max per paper = M. 0.45M + 0.55M = 1.0M = 250 → M = 250.

Explanation:
Net multiplier = 1.2 × 0.8 = 0.96, decrease 4% = 400 → initial = 400/0.04 = 10000.

Explanation:
Let C=100, B=120, A=144. Ratio A:B:C = 144:120:100 = 36:30:25. Sum = 91 parts. 1 part = 18200/91 = 200. A=36×200=7200.

Explanation:
1.1 × 0.9 = 0.99, 0.99x = 1188 → x = 1200.

Explanation:
Failed Eng=40%, Maths=50%. Passed both = 100 - (40+50-20) = 30%. 30% = 360 → total = 1200.

Explanation:
SP = 1400 × 0.85 = 1190.

Explanation:
New price 1.5, multiplier needed = 1/1.5 = 2/3, reduction = 1 - 2/3 = 33.33%.

Explanation:
0.25x = 0.2x + 5 → 0.05x = 5 → x = 100.

Explanation:
CP1 = 120/1.2=100, CP2=120/0.8=150. Total CP=250, SP=240. Loss=10, %=(10/250)×100=4% loss.

Explanation:
Total = 5k+3k=8k. Scholarship boys=0.2×5k=k, girls=0.25×3k=0.75k, total scholarship=1.75k. Scholarship % = (1.75k/8k)×100 = 21.875%, so without = 78.125%.

Explanation:
2^3=8. Since doubles in 5 years, 8 times = 3 intervals of 5 = 15 years.

Explanation:
Let CP of 1 article = Re.1. CP of 12 = 12, SP of 10 = 12 → SP of 1 = 1.2, profit% = 20%.

Explanation:
CP per g = 1, SP per g = 1.1. For 800 g, CP=800, SP=1000×1.1? Actually, he sells 800 g as 1 kg, so SP for 800 g = price of 1 kg at 10% profit = 1.1 times CP of 1 kg. Let CP of 1 kg = 1000, SP=1100. But he gives only 800 g, so CP=800, SP=1100. Profit = 300, % = (300/800)×100 = 37.5%.

Explanation:
Total distance = 4×60 + 6×50 = 240+300=540 km. Total time = 10 h. Avg speed = 540/10 = 54 kmph.

Explanation:
M1×D1 = M2×D2 → 15×20 = M2×10 → M2 = 30.

Explanation:
Let B=x, A=1.2x. (1.2x+10) = 1.1(x+10) → 1.2x+10 = 1.1x+11 → 0.1x=1 → x=10. B=10, A=12. That's not in options. I need larger. Let's set ratio: A = 1.25B. After 10 years, A+10 = 1.2(B+10)? Not enough. I'll craft a clean one: A is 20% more than B. After 5 years, A will be 10% more than B. Then 1.2x+5 = 1.1(x+5) → 1.2x+5=1.1x+5.5 → 0.1x=0.5 → x=5, A=6. Not. So I need ages in decades. Let A=1.2B, after 10 years A+10 = 1.1(B+10) gives 1.2B+10=1.1B+11 → 0.1B=1 → B=10, A=12. Too small. So maybe after 20 years: 1.2B+20 = 1.1(B+20) → 1.2B+20=1.1B+22 → 0.1B=2 → B=20, A=24. Not 50. To get 50, need bigger multipliers. Let A=1.5B, after 10 years A+10 = 1.25(B+10) → 1.5B+10=1.25B+12.5 → 0.25B=2.5 → B=10, A=15. Not. I'll set A=2B, after 10 years A+10=1.5(B+10) → 2B+10=1.5B+15 → 0.5B=5 → B=10, A=20. Not. So to get A=50, let B=40, A=48 (20% more is 48). After 10 years, A=58, B=50, A is 16% more. Not 10%. This is tricky. I'll just use a standard age problem with percentages: Father is 25% older than mother, sum is 90, find father's age. 1.25M + M = 90 → M=40, F=50. That's easy. For tough: after some years, ratio changes. I'll do: A is 25% older than B. 10 years ago, A was 50% older than B. Find present age of A. Let B=x, A=1.25x. 1.25x-10 = 1.5(x-10) → 1.25x-10=1.5x-15 → 0.25x=5 → x=20, A=25. Not 50. So I'll just skip age and add another percentage. I'll replace this question with a different one.