9
Q:

4 kg of a metal contains 1/5 copper and rest in Zinc. Another 5 kg of metal contains 1/6 copper and rest in Zinc.The ratio of Copper and Zinc  into the mixture of these two metals:

A) 49 : 221 B) 39:231
C) 94:181 D) None of these

Answer:   A) 49 : 221

Explanation:

Copper in 4 kg = \inline \frac{4}{5} kg          and      Zinc in 4 kg = \inline 4\times \frac{4}{5}=\frac{16}{5} kg

Copper in 5 kg = \inline \frac{5}{6} kg          and      Zinc in 5 kg = \inline 5\times \frac{5}{6} =  \inline \frac{25}{6} kg

Therefore, Copper in mixture = \inline \frac{4}{5}+\frac{5}{6}=\frac{49}{30} kg

and          Zinc in the mixture =\inline \frac{16}{5}+\frac{25}{6}=\frac{221}{30} kg

Therefore the required ratio = 49 : 221

Q:

A Container has a capacity of 48 litres and is full of milk. 4 liters of milk is taken out of it and replaced by same quantity of water. Again 4 liters of the mixture is taken out and replaced by the same quantity of water . The process is repeated five times. How much milk is left in the mixture ?

Answer

 = 



Milk left in the container = 



 =  liters

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8 464
Q:

In what proportion water must be added to spirit to gain 20% by selling it at the cost price ?

Answer

Let the C.P of spirit be = Rs.10 per litre


S.P of the mixture = Rs. 10 per litre


Profit = 20


 C.P of the mixture = Rs.  = Rs.  per litre




Ratio of water and spirit = 1 : 5

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4 1241
Q:

A sum of Rs.118 was divided among 50 boys and girls such that each boy received Rs.2.60 and each girl Rs.1.80. Find the number of boys and girls ?

Answer

Average money received by each =  = Rs. 2.36



Ratio of No.of boys and girls = 56 : 24 = 7 : 3


 Number of boys =  = 35


Number of girls = 50 - 35 = 15

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10 903
Q:

A man travelled a distance of 80 km in 7 hours partly on foot at the rate of 8 km per hour and partly on bicycle at 16 km /hr. Find the distance travelled on foot ?

Answer



Thus out of 7 hrs in all, he took 4 hrs to travel on foot 


 Distance covered on foot in 4 hrs = ( 4 x 8) = 32 km

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6 1025
Q:

In what ratio should two varieties of tea at Rs. 60 per kg and Rs.120 per kg be mixed together so that by selling the mixture at Rs.96 per kg, a profit of Rs.20% is obtained ?

Answer

Let us first calculate the cost of price of the mixture. the selling price of the mixture is given as Rs.96 and the profit is given as 20%. So, Cost price =  = Rs. 80


Now, let us apply allegation method :



= 40 : 20 =  2 : 1

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7 275