Answer: B Total cost price of 200 kg of mixtures = Rs (80*6.75 + 120*8) = Rs 1500 Average rate = Rs 7.50 per kg Required selling price = 7.50 * 1.2 = Rs 9 per kg.
Q. No. 8:
Three mixtures containing milk ans water in the ratio 5:1, 2:1 and 3:1 are mixed in the ratio of 1:2:3. The ratio of milk to water in the resultant mixture is
Answer: D :Lets take, 12 litre of 5 :1 sample 24 litre of 2:1 sample, and 36 litre of 3:1 sample. Amount of milk in the final mixture => (5/6*12) + (2/3*24) + (3/4*36 )= 53L Amount of water in the final solution mixture = 72 -53 = 19 Thus the ratio of milk:water = 53:19
Q. No. 9:
There are two vessels which are filled only with the pure components. Vessel I contains 20L brandy and vessel II contains 20L water. From vessel I, 5L brandy is taken and placed in vessel II. Then 4L mixture is transferred from vessel II to vessel I. Find the ratio of water in vessel I to brandy in vessel II.
Answer: C When 5L brandy is transferred, volume of brandy let in vessel I =15L Volume of brandy in vessel II =5L Volume of water in vessel II = 20L Now, 4L of mixture containing brandy and water in the ratio 1:4 is poured into pure brandy of volume 15L. 4L of mixture contains 3.2L water and 0.8 L brandy. Volume of brandy left in vessel II = (5 - 0.8) = 4.2 L Ratio of water in vessel I to brandy in vessel II = 3.2 : 4.2 => 16:21
Q. No. 10:
A container contains 89 kg milk. From this, 8 kg milk was taken out and replaced by water. This process is repeated thrice. What is the ratio of the quantity of milk after the first draw to quantity of milk left after the third draw?
Answer: B Quantity of milk after first draw = 90/100 * 80 = 72kg. Quantity of milk after second draw = 90/100 * (90/100 * 80) = 64 kg Quantity of milk after third draw = 9/10 * 9/10 * 9/10 * 80 = 58.32 Thus ratio = 100:81.
Q. No. 11:
A has 73L wine in a drum. He replaces 3.65 L of it with water and keeps doing so till the time the concentration of wine is less than 85%. The minimum number of operations that A has to perform is
Answer: D In, fact , A takes out 5% of the existing volume of wine in every operation. After the first operation concentration of wine is 95%. After the second operation concentration of wine is 95* 0.95 = 90.25% After the third operation concentration of wine is 90.25 * 0.95 = 85.7375% Obviously, in the fourth operation the concentration of wine will be less than 85%.
Q. No. 12:
A 40L solution contains spirit and water in the ratio 3:1. How much water should be added to bring the ratio 5:2?
Answer: A In the original mixture, spirit = 3/4 * 40 = 30L water = 1/4 * 40 = 10L To get the ratio 5:2, lets assume that we add x 30/(10+x) =5/2 => x= 2L, Thus 2L of water has to be added.