Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: · Marks: · Difficulty:
In two types of powdered detergent the ratio of soda and soap-dust is 2 : 19 and 1 : 11 respectively. If 7 kg of the first type is mixed with 4 kg of the second type, find the ratio of soda to soap-dust in the new detergent mixture.
(a)1 : 9
(b)9 : 1
(c)1 : 10
(d)20 : 1
Answer
Answer (as printed): C
Explanation
Quantity of soda in the mixture $$=\left(7 \times \frac{2}{21}+4 \times \frac{1}{12}\right) \mathrm{kg}=\left(\frac{2}{3}+\frac{1}{3}\right) \mathrm{kg}=1 \mathrm{kg} .$$ Quantity of soap-dust in the mixture $$=[(7+4)-1] \mathrm{kg}=10 \mathrm{kg} .$$ ∴ Required ratio $=1: 10$.