# Practice Allegations Mixture Based - Quantitative Aptitude Online Quiz (Set-1) For All Competitive Exams

#### Q-1) A sugar solution of 3 litre contain 60% sugar. One liter of water is added to this solution. Then the percentage of sugar in the new solution is:

(a)

(b)

(c)

(d)

**Explanation:**

Quantity of sugar in the solution = ${3 × 60}/100 = 1.8$units

On adding 1 litre of water,

Required percent = $1.8/4 × 100 = 45%$

#### Q-2) If 4 litres of water is evaporated on boiling from 12 litres of salt solution containing 7 percentage salt, the percentage of salt in the remaining solution is

(a)

(b)

(c)

(d)

**Explanation:**

In 12 litres salt solution,

Salt = ${7 × 12}/100 = 0.84$ units

Water = ${93 × 12}/100 = 11.16$ units

After evaporation,

Percentage of salt = $0.84/8 × 100 = 10.5$%

#### Q-3) 8 litres of water is added to 32 litres of a solution containing 20% of alcohol in water. What is the approximate concentration of alcohol in the solution now ?

(a)

(b)

(c)

(d)

**Explanation:**

In 32 litres of solution,

Alcohol = ${32 × 20}/100$ = 6.4 litres

Water = 32 – 6.4 = 25.6 litres

On adding 8 litres of water,

Required percent = $6.4/40 × 100$ = 16%

#### Q-4) An ore contains 25% of an alloy that has 90% iron. Other than this, in the remaining 75% of the ore, there is no iron. To obtain 60 kg of pure iron, the quantity of the ore needed (in kgs) is approximately :

(a)

(b)

(c)

(d)

**Explanation:**

In 4 kg of ore, iron = 0.9 kg.

Quantity of ore for 60 kg of iron

= ${60 × 4}/0.9$ = 266.67 kg

#### Q-5) A litre of pure alcohol is added to 6 litres of 30% alcohol solution. The percentage of water in the solution is

(a)

(b)

(c)

(d)

**Explanation:**

In 30% alcohol solution,

Alcohol = $30/100 × 6$ =1.8litres

Water = 4.2 litres

On mixing 1 litre of pure alcohol,

Percentage of water =$4.2/7 × 100$ = 60%

#### Q-6) In what ratio must 25% of alcohol be mixed with 50% of alcohol to get a mixture of 40% strength alcohol ?

(a)

(b)

(c)

(d)

**Explanation:**

Required ratio = $1/10 : 3/20 = 2 : 3$

#### Q-7) How much water must be added to 100 ml of 80 per cent solution of boric acid to reduce it to a 50 per cent solution ?

(a)

(b)

(c)

(d)

**Explanation:**

Let x ml of water be added.

${20 + x}/{100 + x} × 100$ = 50

40 + 2x = 100 + x ⇒ x = 60 ml

#### Q-8) In 50 gm alloy of gold and silver, the gold is 80% by weight. How much gold should be mixed to this alloy so that the weight of gold would become 95% ?

(a)

(b)

(c)

(d)

**Explanation:**

Initial quantity of gold

= ${50 × 80}/100$ = 40 gm

Let 'x ' gm be mixed.

$(40 + x) = (50 + x) × 95/100$

$40 + x =(50 + x) × 19/20$

800 + 20x = 950 + 19x

x = 150 gm

#### Q-9) The ratio in which two sugar solutions of the concentrations 15% and 40% are to be mixed to get a solution of concentration 30% is

(a)

(b)

(c)

(d)

**Explanation:**

Required ratio = 10 : 15 = 2 : 3

#### Q-10) How much pure alcohol has to be added to 400 ml of a solution containing 15% of alcohol to change the concentration of alcohol in the mixture to 32% ?

(a)

(b)

(c)

(d)

**Explanation:**

Alcohol = $(15/100 × 400)$ml = 60 ml.

Water = 340 ml.

Let x ml of alcohol be added.

Then, ${60 + x}/{400 + x} × 100 = 32$

or ${60 + x}/{400 + x} = 32/100 = 8/25$

or 1500 + 25x = 3200 + 8x

or 17x = 1700

or x = 100 ml