Question: 41 -

How many kilograms of rice costing Rs. 9 per kg must be mixed with 27kg of rice costing Rs.7 per kg so that there may be gain of 10% by selling the mixture at Rs.9.24 per kg?

56

35

49

63

Answer:

63

Solution:

By rule of allegation: –
9        7
….8.4…..
1.4     0.6
So, x/27 = 1.4/0.6, we get x = 63 kg

Question: 42 -

Two cans P and Q contains milk and water in the ratio of 3:2 and 7:3 respectively. The ratio in which these two cans be mixed so as to get a new mixture containing milk and water in the ratio 7:4.

 7:5

 7:4

7:3

4:7

Answer:

 7:4

Solution:

Milk in 1st can = 3/5 and water = 2/5. Similarly in second can milk = 7/10 and water = 3/10.
Take the ratio = K:1
(3k/5 + 7/10)/(2k/5 + 3/10) = 7/4
Solve for k, we get k = 7/4. So the ratio is 7:4

Question: 43 -

A sample of x litre is replaced from a container containing milk and water in the ratio 2:3 by pure milk. If the container hold 30 litres of the mixture, and after the operation proportion of milk and water is same. Find the value of X?

7

4

6

5

Answer:

5

Solution:

milk = 30*2/5 = 12 and water = 30*3/5 = 18
milk = 12 – x*2/5 + x and water = 18 – x*3/5
equate both equation and we get x = 5

Question: 44 -

How many litres of water must be added to 60 litre mixture that contains milk and water in the 7:3 such that the resulting mixture has 50% water in it?

28

16

24

12

Answer:

24

Solution:

milk = (7/10)*60 = 42 and water = 18
so water must be added = 42 – 18 = 24

Question: 45 -

A trader mixes 6ltr of milk costing 5000 rupees with 7ltr of milk costing 6000 rupees per litre. The trader also mixes some quantity of water to the mixture so as to bring the price to 4800 per litre. How many litres of water is added

3ltr

4ltr

1ltr

2ltr

Answer:

2ltr

Solution:

6*5000 + 7*6000)/(13 + w) = 4800 (w is the amount of water added)