Question

In what ratio must water be mixed with milk to gain $16\frac{2}{3}$% on selling the mixture at cost price?

• A. $1:6$
• B. $6:1$
• C. $2:3$
• D. $4:3$

Answer 1

The correct option is A $1:6$

Let C.P. of $1$ litre milk be Re. $1$.
S.P. of $1$ litre of mixture $=$ Re. $1$, Gain $=\frac{50}{3}$%.
$\therefore$ C.P. of $1$ litre of mixture $=(100\times \frac{3}{350}\times 1)=\frac{6}{7}$
By the rule of alligation, we have:
$\therefore$ Ratio of water and milk $=\frac{1}{7}:\frac{6}{7}=1:6$