Mixtures and Alligation Questions

Multiple choice
  1. 9

  2. 12

  3. 3

  4. 5

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let capacity = x liters. After first replacement: milk = x-3. After second: milk = (x-3)²/x. Final milk ratio = 4/9, so (x-3)²/x² = 4/9. Solving: 3(x-3) = 2x, giving x = 9. Verification: after two operations, milk fraction = (6/9)² = 36/81 = 4/9 ✓

Multiple choice
  1. 0.88%

  2. 0.75%

  3. 0.98%

  4. 0.90%

  5. cannot be determined

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Track the milk through each transfer: initially A has 100 water, B has 100 milk. After 10% of A (10 water) moves to B, B has 110 total (100 milk + 10 water). When 10% of B (11 units) moves to C, it contains 10 milk and 1 water. Finally, 10% of C (11.1 units) moves back to A. The milk reaching A is 11 × 10/111 = 0.99 units out of A's final 101.1 units, giving 0.98%. This successive percentage problem requires tracking composition changes at each step.

Multiple choice
  1. 6

  2. 7

  3. 14

  4. 9

  5. 8

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let x liters from first mixture (3:7 alcohol:water) and (36-x) from second (5:11 alcohol:water). Total alcohol = 3x/7 + 5(36-x)/11 = 36 × 4/9 = 16. Solving 33x + 180(36-x) = 1232 gives 33x - 180x = 1232 - 6480, so x = 14 liters.

Multiple choice
  1. 110 lit/ली.

  2. 99 lit/ली.

  3. 121 lit/ली.

  4. 123 lit/ली.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Initially, let A = 6x litres and B = 11x litres (total 17x). When 34 litres is drawn, it removes (6/17)×34 = 12 litres of A and (11/17)×34 = 22 litres of B. After adding 23 litres of A, new A = 6x - 12 + 23 = 6x + 11, and new B = 11x - 22. New ratio (6x+11)/(11x-22) = 7/9 gives x = 11. Initial B = 11x = 121 litres. Option A (110 litres) would result if you mistakenly used the new ratio differently. Option D (123 litres) doesn't satisfy the equation.

Multiple choice
  1. 10 litre /लीटर

  2. 15 litre /लीटर

  3. 20 litre /लीटर

  4. 25 litre /लीटर

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let P = 5x, Q = 2x. After removing 14 litres: remaining P = 5x - (14 × 5/7) = 5x - 10, remaining Q = 2x - (14 × 2/7) = 2x - 4. After adding 14 litres Q: new Q = 2x - 4 + 14 = 2x + 10. New ratio P:Q = 7:9, so (5x - 10)/(2x + 10) = 7/9. Cross-multiply: 9(5x - 10) = 7(2x + 10), giving 45x - 90 = 14x + 70, so 31x = 160, x = 160/31. P = 5x = 800/31 ≈ 25.8 litres, approximately 25 litres. Option D is correct.

Multiple choice
  1. 1 litre/लीटर

  2. 2 litre/लीटर

  3. 3.5 litre/लीटर

  4. 2.5 litre/लीटर

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Initial mixture: 10 litres with 10% acid = 1 litre acid, 9 litres other. Let x be litres of pure acid added. Final mixture: (1+x) litres acid in (10+x) total litres. We need (1+x)/(10+x) = 25/100 = 1/4. Solving: 4(1+x) = 10+x → 4+4x = 10+x → 3x = 6 → x = 2 litres. Option B is correct.

Multiple choice
  1. 20 gm

  2. 25 gm

  3. 18 gm

  4. 19 gm

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Current mixture: 80 gm with gold:brass = 5:3. So gold = (5/8)*80 = 50 gm, brass = (3/8)*80 = 30 gm. Let x gm brass be added. Then brass = 30+x, total = 80+x. For brass to be 50%: (30+x)/(80+x) = 1/2. Solving: 60+2x = 80+x, so x = 20 gm. Final mixture: 50 gm gold, 50 gm brass.

Multiple choice
  1. 48

  2. 58

  3. 40

  4. 50

  5. 68

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Initial A:B:C = 3:4:9, total = 16x = mixture quantity. After removing 10L, remaining is 16x - 10. After adding 3L each: A = 3x - (30/16x) + 3, B = 4x - (40/16x) + 3, C = 9x - (90/16x) + 3. Given C = 3B, solving gives x = 3.625, so initial = 58L.

Multiple choice
  1. 3 : 5

  2. 4 : 7

  3. 3 : 8

  4. 5 : 11

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alloy 1: copper = 1/4, tin = 3/4. Alloy 2: copper = 2/7, tin = 5/7. Let mix in ratio x:y. Total tin = 3x/4 + 5y/7, total copper = x/4 + 2y/7. Tin:Cu = 8:3 gives (3x/4 + 5y/7) ÷ (x/4 + 2y/7) = 8/3. Solving yields x:y = 4:7.

Multiple choice
  1. 2 लीटर

  2. 2.5 लीटर

  3. 3 लीटर

  4. 3.5 लीटर

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In 42 litres with ratio 4:3, milk = (4/7) × 42 = 24 litres, water = (3/7) × 42 = 18 litres. After removing x litres each: (24 - x)/(18 - x) = 7/5. Cross-multiplying: 5(24 - x) = 7(18 - x). So 120 - 5x = 126 - 7x, giving 2x = 6 and x = 3 litres.

Multiple choice
  1. 35 Lt./ली.

  2. 25 Lt./ली.

  3. 15 Lt./ली.

  4. 20 Lt./ली.

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let original water be x liters. After removing 10L and adding wine: (x-10) water remains and 10L wine. Ratio is (x-10):10 = 5:2. So x-10 = 50/2 = 25, thus x = 35L. Verify: 25L water - 10L = 15L water, 10L wine added, ratio 15:10 = 3:2 = 5:2 ✓

Multiple choice
  1. 20 litres/ लीटर

  2. 60 litres/ लीटर

  3. 40 litres/ लीटर

  4. 50 litres/ लीटर

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let capacity be C litres. After first operation: paint = C-5, thinner = 5. After second operation (removing 5 litres of mixture): paint remaining = (C-5) - 5(C-5)/C = (C-5)(C-5)/C. The ratio paint:total volume becomes (C-5)²/C² = 49/64 (since 49:(49+15) = 49:64). Solving (C-5)²/C² = 49/64 gives (C-5)/C = 7/8, so 8C-40 = 7C, hence C = 40.

Multiple choice
  1. 2 : 3

  2. 4 : 3

  3. 3 : 2

  4. 3 : 4

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Container 1: A:B = 5:1, so fraction of A = 5/6. Container 2: A:B = 1:3, so fraction of A = 1/4. Let mixing ratio be x:y. Total A = (5/6)x + (1/4)y. Total B = (1/6)x + (3/4)y. For A:B = 1:1, we need (5/6)x + (1/4)y = (1/6)x + (3/4)y. Simplifying: (4/6)x = (2/4)y, so (2/3)x = (1/2)y, giving x:y = 3:4.

Multiple choice
  1. 50 litre /लीटर

  2. 55 litre /लीटर

  3. 60 litre /लीटर

  4. 100 litre /लीटर

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Initial: 50 litres with milk:water = 2:1, so milk = 100/3 L, water = 50/3 L. Let x be added water. For 1:2 ratio: (100/3)/((50/3)+x) = 1/2. Solving gives 100/3 = (50/3 + x)/2, so x = 50 L. Option A is correct.