Question

If 12 pencils cost ₹ 60, how much will 7 pencils cost?

• A. ₹ 5
• B. ₹ 35
• C. ₹ 14
• D. ₹ 7

Answer 1

The correct option is B ₹ 35

Cost of 12 pencils = ₹ 60.
If the number of pencils decreases, the cost also decreases.
$\therefore$ This is a case of direct proportion.
Using the formula for direct proportion,
$\frac{\text{Cost of pencils}}{\text{Number of pencils}}=\text{constant}$
$\Rightarrow \frac{60}{12}=\frac{\text{Cost of 7 pencils}}{7}$
$\therefore \text{Cost of 7 pencils}=\frac{60}{12}\times 7=₹35$