Question

The total cost of 30 identical erasers is y dollars. At this rate, find the total cost in dollars of 70 of these erasers in terms of y.

• A. $\frac{3y}{7}$
• B. $\frac{4y}{7}$
• C. $\frac{7y}{4}$
• D. $\frac{7y}{3}$
• E. $70y$

Answer 1

The correct option is D $\frac{7y}{3}$

Given that,

The cost of $30$ erasers is $y$ dollars.

To find out,

The cost of $70$ erasers.

The cost of $30$ erasers $=y$ dollars

Hence, the cost of one eraser $=\frac{y}{30}$ dollars [unitary method]

$\therefore$ The cost of $70$ erasers $=\frac{y}{30}\times 70$

$=\frac{7y}{3}$ dollars.

Hence, the cost of $70$ erasers is $\frac{7y}{3}$ dollars.