Monthly consumption of kerosene oil in a certain household along with price variations is given below. | Rate of kerosene oil (in ₹) | 1.5 | 2 | 3.0 | 4.5 | |---|---|---|---|---| | Consumption (in litres) | 60 | 45 | 30 | 20 | When the price goes up to ₹ 6 per litre, what is the likely consumption of kerosene?

### Concept & Inverse Proportion When two variables are inversely proportional, their product remains constant. In financial terms, if a budget is fixed, the Total Expenditure (Rate $\times$ Consumption) is constant. ### Step-by-Step Solution 1. Analyze the given table to determine the relationship between the rate ($R$) and consumption ($C$). 2. Calculate the product $R \times C$ for each data point: - $1.5 \times 60 = 90$ - $2 \times 45 = 90$ - $3.0 \times 30 = 90$ - $4.5 \times 20 = 90$ 3. Since the product is consistently 90, the total monthly expenditure is fixed at ₹90. The variables are inversely proportional. 4. Establish the equation for the relationship: $$ R \times C = 90 $$ 5. The question asks for the consumption when the rate is ₹6 per litre ($R = 6$). 6. Substitute $R = 6$ into the equation: $$ 6 \times C = 90 $$ $$ C = \frac{90}{6} = 15 \text{ litres} $$ ### Exam Strategy & Shortcut Use proportional reasoning on the table directly. Notice the relationship between the first column and the third column: the rate doubles ($1.5 \rightarrow 3.0$), causing the consumption to halve ($60 \rightarrow 30$). Apply this same logic to find the unknown: from a rate of $3.0$ to $6.0$, the rate doubles again. Consequently, the consumption must halve from what it was at $3.0$. Half of 30 is 15. ### Common Pitfall Attempting to find an additive arithmetic pattern between the terms (like subtracting a constant amount) instead of recognizing the multiplicative inverse relationship. ### Final Answer Therefore, the correct answer is **15 litres**.