Ratio and Proportion

Concept:The wages bill is the product of the number of employees and the wage per employee.Explanation:Let the initial number of employees be $9x$ and the initial wage per employee be $14y$.Then, the initial wages bill = $9x \times 14y = 126xy$.After the change, the number of employees becomes $8x$ and the wage per employee becomes $15y$.So, the new wages bill = $8x \times 15y = 120xy$.The ratio of the old bill to the new bill is $126xy : 120xy$, which simplifies to $21 : 20$.This means the bill decreases from $21$ parts to $20$ parts, i.e., in the ratio $21 : 20$.Answer:C. $21 : 20$