Here we are with another aptitude test for competitive exams. We have a collection of 36 Alligation & Mixture questions for practice. You’ll learn how to balance mixtures like a chef(with math skills), not a guesser. The set covers mixing ratios, dilution, and weighted average logic. Each question has an answer for quick self-check.
In addition we have have lot of other aptitude question and answers. You might want to check out that too.
36 Alligation or Mixture Aptitude Questions and Answers (Solved MCQs)
Question 1. In what ratio should sugar at ₹30/kg be mixed with sugar at ₹50/kg to get a mixture worth ₹42/kg?
a) 1:2
b) 2:3
c) 3:2
d) 5:2
Answer:
b) 2:3 — Cheaper:dearer = (50−42):(42−30).
Question 2. In what ratio should 4% milk be mixed with 10% milk to get 7% milk?
a) 1:2
b) 2:1
c) 1:1
d) 3:2
Answer:
c) 1:1 — Equal deviations from 7%.
Question 3. In what ratio should 20% acid be mixed with 50% acid to get 35% acid?
a) 1:2
b) 2:1
c) 1:1
d) 3:2
Answer:
c) 1:1
Question 4. Tea at ₹200/kg is mixed with tea at ₹320/kg. In what ratio should they be mixed to get ₹260/kg?
a) 2:1
b) 1:2
c) 1:1
d) 3:2
Answer:
c) 1:1 — Deviations are equal (60 and 60).
Question 5. In what ratio should a 5% solution be mixed with a 20% solution to get an 11% solution?
a) 2:3
b) 3:2
c) 4:3
d) 5:4
Answer:
b) 3:2 — (20−11):(11−5) = 9:6.
Question 6. A mixture contains liquids in ratio 3:5. If their prices are ₹18/L and ₹42/L, find mean price per litre.
a) ₹30
b) ₹33
c) ₹36
d) ₹39
Answer:
b) ₹33 — Weighted mean = (3×18 + 5×42)/8.
Question 7. A mixture contains oils in ratio 7:3. If prices are ₹80/L and ₹140/L, find mean price per litre.
a) ₹92
b) ₹98
c) ₹104
d) ₹110
Answer:
b) ₹98
Question 8. How many litres of 15% solution must be added to 40 L of 30% solution to make it 25%?
a) 10 L
b) 15 L
c) 20 L
d) 25 L
Answer:
c) 20 L — Balance solute: 12 + 0.15x = 0.25(40+x).
Question 9. In what ratio should rice at ₹28/kg be mixed with rice at ₹35/kg to get ₹32.20/kg?
a) 3:2
b) 2:3
c) 4:3
d) 5:2
Answer:
b) 2:3 — (35−32.2):(32.2−28) = 2.8:4.2.
Question 10. A 12% solution is mixed with a b% solution in ratio 5:3 to get 18%. Find b.
a) 24%
b) 26%
c) 28%
d) 30%
Answer:
c) 28% — (5×12 + 3b)/8 = 18.
Question 11. In what ratio should 92-octane petrol be mixed with 98-octane petrol to get 95-octane petrol?
a) 1:3
b) 2:1
c) 1:1
d) 3:2
Answer:
c) 1:1 — Deviations are equal (3 and 3).
Question 12. In what ratio should 1/3 pure alcohol be mixed with 3/4 pure alcohol to get 60% alcohol?
a) 16:9
b) 9:16
c) 3:5
d) 5:3
Answer:
b) 9:16 — (45−36):(36−20) using /60 equivalents.
Question 1. A 30 L vessel is full of milk. 6 L is removed and replaced with water (once). What is the percentage of milk now?
a) 70%
b) 75%
c) 80%
d) 84%
Answer:
c) 80% — Milk left = 30×(24/30).
Question 2. A 20 L vessel is full of milk. 5 L is removed and replaced with water, repeated 3 times. What % of milk remains?
a) 31.64%
b) 42.19%
c) 52.00%
d) 57.81%
Answer:
b) 42.19% — Fraction left = (15/20)³ = 27/64.
Question 3. A 25 L vessel is full of wine. 5 L is removed and replaced with water, repeated twice. How much wine remains?
a) 12.8 L
b) 14.4 L
c) 16 L
d) 18 L
Answer:
c) 16 L — Wine left = 25×(20/25)².
Question 4. A 40 L solution contains 25% acid. 10 L is removed and replaced with water (once). What is new acid %?
a) 12.5%
b) 15%
c) 18.75%
d) 20%
Answer:
c) 18.75% — Acid retained = 0.75 of original.
Question 5. A 40 L solution contains 25% acid. 10 L is removed and replaced with water, repeated twice. What is new acid %?
a) 12.5%
b) 14.0625%
c) 16.25%
d) 18.75%
Answer:
b) 14.0625% — Acid fraction = (30/40)².
Question 6. A 50 L salt solution is 10% salt. 5 L is removed and replaced with water, repeated 4 times. Find final salt %.
a) 5.61%
b) 6.56%
c) 7.29%
d) 8.10%
Answer:
b) 6.56% — Fraction left = (45/50)⁴ = 0.6561.
Question 7. A 30 L vessel is full of juice. x L is removed and replaced with water once. Now juice is 20%. Find x.
a) 18 L
b) 20 L
c) 24 L
d) 26 L
Answer:
c) 24 L — (30−x)/30 = 0.20.
Question 8. An 18 L vessel is full of alcohol. 3 L is removed and replaced with water, repeated twice. How much alcohol remains?
a) 10.0 L
b) 11.5 L
c) 12.5 L
d) 13.5 L
Answer:
c) 12.5 L — Alcohol left = 18×(15/18)².
Question 9. A 60 L mixture contains 75% milk. 12 L is removed and replaced with water once. What is new milk %?
a) 50%
b) 55%
c) 60%
d) 65%
Answer:
c) 60% — Milk retained factor = 48/60.
Question 10. A 20 L tank has 30% acid. 4 L is removed and replaced with water, repeated twice. Find final acid %.
a) 16.8%
b) 18.0%
c) 19.2%
d) 21.0%
Answer:
c) 19.2% — Acid fraction = (16/20)².
Question 11. A 32 L solution contains 40% alcohol. 8 L is removed and replaced with water, repeated 3 times. Find final alcohol %.
a) 12.5%
b) 15.0%
c) 16.875%
d) 18.0%
Answer:
c) 16.875% — Fraction left = (24/32)³.
Question 12. A 40 L vessel is full of milk. x L is removed and replaced with water, repeated twice. Now milk is 25%. Find x.
a) 10 L
b) 15 L
c) 20 L
d) 25 L
Answer:
c) 20 L — (1−x/40)² = 0.25.
Question 1. 10 L of 20% acid, 15 L of 50% acid, and 25 L water are mixed. Find final acid %.
a) 16%
b) 18%
c) 19%
d) 21%
Answer:
c) 19% — Acid = 2 + 7.5 out of 50 L.
Question 2. Blend A: 40 L at 30% sugar. Blend B: 60 L at 20% sugar. If mixed, find final sugar %.
a) 22%
b) 24%
c) 25%
d) 26%
Answer:
b) 24% — Weighted mean of concentrations.
Question 3. Make 60 L oil at ₹84/L using ₹72/L and ₹96/L oils. How many litres of each are needed?
a) 20 L and 40 L
b) 30 L and 30 L
c) 40 L and 20 L
d) 45 L and 15 L
Answer:
b) 30 L and 30 L — Ratio 1:1 by alligation.
Question 4. Rice at ₹24, ₹30, ₹42 are mixed in ratio 2:3:1. Find mean price per kg.
a) ₹28
b) ₹30
c) ₹32
d) ₹34
Answer:
b) ₹30 — (2×24 + 3×30 + 1×42)/6.
Question 5. You must prepare 50 L of 26% acid using 40 L of 20% acid and 10 L of 50% acid. Is it possible?
a) No, it becomes 24%
b) No, it becomes 25%
c) Yes, it becomes 26%
d) Yes, it becomes 28%
Answer:
c) Yes, it becomes 26% — Acid = 8 + 5 = 13 in 50.
Question 6. Alloy X: 25 kg with 60% copper. Alloy Y: x kg with 80% copper. Find x to get 70% copper overall.
a) 15 kg
b) 20 kg
c) 25 kg
d) 30 kg
Answer:
c) 25 kg — Balance copper: 15+0.8x = 0.7(25+x).
Question 7. Coffee at ₹480/kg and ₹660/kg is mixed and sold at ₹690/kg with 15% profit. Find mixing ratio (₹480 : ₹660).
a) 1:1
b) 1:2
c) 2:1
d) 3:2
Answer:
b) 1:2 — CP = 690/1.15 = 600; ratio (660−600):(600−480).
Question 8. 12 L of 10% solution and 8 L of 25% solution are mixed. How many litres of 40% solution must be added to make the final mixture 25%?
a) 8 L
b) 10 L
c) 12 L
d) 14 L
Answer:
c) 12 L — 3.2+0.4x = 0.25(20+x).
Question 9. Make 45 kg alloy at 30% tin using 20% and 50% tin alloys. Find quantities of 20% and 50% alloys.
a) 15 kg and 30 kg
b) 20 kg and 25 kg
c) 30 kg and 15 kg
d) 33 kg and 12 kg
Answer:
c) 30 kg and 15 kg — Ratio (50−30):(30−20) = 2:1.
Question 10. Pulses at ₹80/kg and ₹110/kg are mixed in ratio 3:2. Find selling price per kg for 10% profit.
a) ₹99.2
b) ₹101.2
c) ₹103.4
d) ₹105.0
Answer:
b) ₹101.2 — CP = 92; SP = 92×1.10.
Question 11. Prepare 50 L of 30% acid using 20% and 40% acids, but 40% acid is limited to 15 L. Find quantities of 20% and 40% acids.
a) 25 L and 25 L
b) 30 L and 20 L
c) 35 L and 15 L
d) 40 L and 10 L
Answer:
c) 35 L and 15 L — With 15 L fixed; solve for remaining.
Question 12. Mixture A has sugar:water = 3:2 and Mixture B has sugar:water = 5:3. If 16 L of A is mixed with x L of B to make 61% sugar, find x.
a) 8 L
b) 10 2/3 L
c) 12 L
d) 14 L
Answer:
b) 10 2/3 L — 0.6×16 + 0.625x = 0.61(16+x).
