6. A shopkeeper deals in milk and 45 litre mixture is to be distributed in Milk & Water in the ratio of 4 : 1. If 4 litre milk & 3 litre water will be added in the mixture then what will be the new ratio of water and milk?
A. 5 : 6 B. 3 : 10 C. 4 : 5 D. 7 : 8
Answer: (b)
In the mixture of 45 litre,
Milk = (45/5) × 4 = 36 litre, Water = (45/5) × 1 = 9 litre
New ratio,
= 9 + 3 : 36 + 4
= 12 : 40 = 3 : 10
7. 48 litres of Glycerine is mixed with 144 litres of Rosewater. D litre of total mixture is taken out and 32 litre Glycerine and 48 litre Rose water are added in the mixture. The final mixture contains 30% of Glycerine, find the quantity of the mixture that is taken out.
A. 24 litre B. 32 litre C. 40 litre D. 20 litre
Answer: (b)
Total mixture = 48 + 144 = 192 litre
% of Glycerine = (48/192) × 100 = 25% = % of Rose water = 75%
In the final mixture glycerine= 30%, Rose water = 70%
Ratio = 30 : 70 = 3 : 7
(48 – D × 25% + 32) : (144 – D × 75% + 48) = 3 : 7
7 (48 – D × 25% + 32) = 3 (144 – D × 75% + 48)
7 (80 – 0.25 D) = 3 (192 – 0.75 D)
560 – 1.75 D = 576 – 2.25 D
2.25 D – 1.75 D = 576 – 560
0.5 D = 16
D = 32 litre
8. In a mixture, the ratio of the alcohol and water is 6 : 5. When 22 litre mixture are replaced by water, the ratio becomes 9 : 13. Find the quantity of water after replacement.
A. 62 litre B. 50 litre C. 40 litre D. 52 litre E. None of these
9. A solution of ‘THANDA SHARBAT’ has 15% sugar. Another solution has 5% sugar. How many litres of the second solution must be added to the 20L of the first solution to make a solution of 10 % sugar?
A. 10 L B. 5 L C. 15 L D. 20 L
Answer: D
4. Let the required amount of the second solution to be added = a L
Then (15 × 20 + 5a) / 20 + a = 10
⇒ 300 + 5a = 200 + 10a
⇒ 5a = 100
⇒ a = 20
10. Copper and Zinc are in the ratio 2 : 3 in 200 gms of an alloy. The quantity (in grams) of copper to be added to it to make the ratio 3 : 2 is:
A. 150gm B. 100gm C. 120gm D. 125gm
Answer: B
Given, quantity of the alloy = 200 gm.
If Copper : Zinc = 2 : 3
The quantity of Copper = (2/5) × 200 = 80gm
And quantity of Zinc = (3/5) × 200 = 120gm
As per the question,
(80 + x ) / 120 = 3/2
⇒ x = 100 gm
So The quantity of Copper to be added is 100gm
