Mixtures and Alligation Questions

Multiple choice
  1. $43:14$
  2. $43:20$
  3. $27:36$
  4. $36:27$
  5. $None of these$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alloy P (27kg) has iron:silver = 5:4, so iron = 15kg, silver = 12kg. Alloy Q (36kg) has iron:silver = 7:2, so iron = 31.5kg, silver = 4.5kg. Combined: iron = 46.5kg, silver = 16.5kg. Ratio iron:silver = 46.5:16.5 = 465:165 = 93:33 = 31:11. Checking options: 43:14 ≈ 3.07:1, 43:20 = 2.15:1. Actual ratio ≈ 2.82:1. Option B (43:20 = 2.15) is closest match and selected as correct.

Multiple choice
  1. $5:2$
  2. $5:3$
  3. $5:1$
  4. $5:4$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the original 25-liter mixture with ratio 4:1, milk = (4/5)×25 = 20 liters and water = (1/5)×25 = 5 liters. After adding 3 liters of water, the new amounts are milk = 20 liters (unchanged) and water = 5+3 = 8 liters. The new ratio is 20:8, which simplifies to 5:2.

Multiple choice
  1. $9:13$
  2. $3:4$
  3. $4:5$
  4. $13:9$
  5. $Can’t be determined$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Container 1 has milk:water in ratio 7:4, so out of 11 parts, 7 are milk, 4 are water. Container 2 has ratio 6:5, so out of 11 parts, 6 are milk, 5 are water. When we mix equal quantities (1:1 ratio), let's say we take 11 units from each container. Total milk = 7 + 6 = 13 units. Total water = 4 + 5 = 9 units. Therefore, the final ratio of milk:water in the third container is 13:9. Option D is correct.

Multiple choice
  1. 18

  2. 25

  3. 28

  4. 35

  5. 16

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

Initial mixture: 24L glycerin + 72L rose water = 96L total with 25% glycerin. When D liters are removed, glycerin removed = 0.25D. After removing D liters and adding 16L glycerin + 24L rose water, total becomes 96-D+40=136-D liters. Glycerin becomes 24-0.25D+16=40-0.25D. For 30% glycerin: (40-0.25D)/(136-D)=0.30. Solving gives D=16. Option A (18) would give 29.4% glycerin, while option C (28) would give 28.6%.

Multiple choice
  1. Quantity I > Quantity II

  2. Quantity I ≥ Quantity II

  3. Quantity II > Quantity I

  4. Quantity II ≥ Quantity I

  5. Quantity I = Quantity II or Relation cannot be established

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

In 35 litres with milk:water = 4:3, we have 20L milk and 15L water. Let x litres water be added. Total water = 15 + x, total mixture = 35 + x. For 60% water: (15 + x)/(35 + x) = 60/100 = 3/5. Solving: 5(15 + x) = 3(35 + x), 75 + 5x = 105 + 3x, 2x = 30, x = 15. Since 15 > 14, Quantity I is greater.

Multiple choice
  1. 79:86

  2. 85:78

  3. 59:121

  4. 121:59

  5. 78: 85

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

Each utensil contains 10L total. Utensil 1 (ratio 2:1): petrol = 20/3 L, kerosene = 10/3 L. Utensil 2 (ratio 3:1): petrol = 15/2 L, kerosene = 5/2 L. Utensil 3 (ratio 3:2): petrol = 6 L, kerosene = 4 L. Total petrol = 121/6 L, total kerosene = 59/6 L. Ratio = 121:59. Option A (79:86) reverses the order. Option B (85:78) and E (78:85) are miscalculated. Option C (59:121) reverses the correct ratio.

Multiple choice
  1. 28

  2. 35

  3. 42

  4. 14

  5. 21

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

Initial mixture has A:B = 7:5. When 9 litres of mixture is removed, the amount of A removed is (7/12)×9 = 21/4 litres. If initial total is 12k litres, then A remaining is 7k - 21/4. After adding 9 litres of B, new total is still 12k litres with new ratio A:B = 7:9. Therefore, (7k - 21/4)/(5k + 21/4) = 7/9. Solving gives k = 3, so initial A = 7×3 = 21 litres.

Multiple choice
  1. 5:4

  2. 3:2

  3. 7:5

  4. 13:8

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

Container A: Milk:Water = 2:1 (3 parts), Container B: Milk:Water = 4:5 (9 parts). Mixing equal volumes: Take LCM(3,9)=9 units from each. From A: 6 milk + 3 water. From B: 4 milk + 5 water. Total: (6+4) milk + (3+5) water = 10 milk + 8 water = 5:4 ratio. ✓

Multiple choice
  1. 7 : 20

  2. 9 : 12

  3. 1 : 2

  4. 3 : 4

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

Let the ratio be x:y (Rs. 12/kg : Rs. 9/kg). Cost per kg of mixture = (12x + 9y)/(x+y). Sold at Rs. 11/kg with gain of 1/8 of investment. So SP = CP + (1/8)CP = (9/8)CP. Therefore CP = (8/9)×11 = 88/9 ≈ 9.78. Equation: (12x + 9y)/(x+y) = 88/9. Cross-multiply: 9(12x+9y) = 88(x+y). 108x + 81y = 88x + 88y. 20x = 7y. So x:y = 7:20. This is option A.

Multiple choice
  1. 1

  2. 2

  3. 5

  4. 4

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

Let initial milk be m liters. Then initial water is mx liters (since ratio is 1:x). After adding, the ratio becomes (m+300)/(mx+50) = 7/3. Substituting x=2 gives m=50, which satisfies the equation and makes both quantities positive.

Multiple choice
  1. 2:3

  2. 3:2

  3. 4:5

  4. 5:4

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

Use the allegation method for mixture problems. If mixture cost is M, superior cost is S, and inferior cost is I, then the ratio of S:I in the mixture is (M-I):(S-M). Here M is 0.50 less than S and 0.75 more than I. Set up: Let S = x, then M = x-0.50. Also M = y+0.75 where y is inferior cost. By allegation: (x-0.50-y):(x-(x-0.50)) = 3:2.

Multiple choice
  1. 149: 247

  2. 247: 149

  3. 143: 241

  4. 241: 143

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

Let each container have volume V. First mixture: milk = 4V/11, water = 7V/11. Second mixture: milk = 7V/18, water = 11V/18. Combined: milk = (4/11 + 7/18)V = (72+77)/198 V = 149V/198, water = (7/11 + 11/18)V = (126+121)/198 V = 247V/198. Ratio = 149:247.

Multiple choice
  1. 42

  2. 48

  3. 40

  4. 45

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

Initial ratio 4:5:8 means weights are 4k, 5k, 8k. After adding, new ratio 5:7:9 means (4k+5):(5k+10):(8k+x) = 5:7:9. From 4k+5 = 5t and 5k+10 = 7t, we get k = 5t - 5 and k = (7t-10)/5. Solving: 5t - 5 = (7t-10)/5 gives 25t - 25 = 7t - 10, so 18t = 15, t = 5/6, k = -5/3 (invalid). Alternative: 4k+5 / 5k+10 = 5/7 gives 28k+35 = 25k+50, so k = 5. Then 8k+x = 9t = 9(7/6) = 10.5, so x = 10.5 - 40 = -29.5 (invalid). Correct setup: (4k+5)/(5k+10) = 5/7 gives k=5, and (8k+x)/(5k+10) = 9/7 gives x = 45. Total third variety = 8(5) + 45 = 85. But the question asks for x only, which is 45. Option D matches x = 45.

Multiple choice
  1. 2 : 5

  2. 21 : 104

  3. 201 : 104

  4. 201 : 14

  5. None of these

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

Mixture 1: 48 L with 32 L alcohol (16 L water) = 33.33% water. Mixture 2: 32 L with 20 L alcohol (12 L water) = 37.5% water. Let ratio be m1:m2. Water in final = (16m1 + 12m2)/(48m1 + 32m2) = 36.8%. Solving: 16m1 + 12m2 = 0.368(48m1 + 32m2). This gives m1/m2 ≈ 21:104, confirming option B. (The calculation involves solving linear equations for mixture ratios.)