In May, John bought the same amount of rice and the same amount of wheat as he had bought in April, but spent ₹ 150 more due to price increase of rice and wheat by 20% and 12%, respectively. If John had spent ₹ 450 on rice in April, then how much did he spend on wheat in May?

The correct answer is ₹ 560.

Let's work through this problem carefully, step by step.

Step 1: Identify what we know from April

John spent ₹ 450 on rice in April.
Let the amount John spent on wheat in April be ₹ W.

Step 2: Calculate May spending on rice

In May, John bought the same quantity of rice, but the price of rice increased by 20%.
Since the quantity is the same, his spending on rice increases by the same 20%.

$\text{May Rice Spending}=450\times \frac{120}{100}=450\times 1.20=\text{₹ 540}$

So the extra amount spent on rice in May = ₹ 540 − ₹ 450 = ₹ 90.

Step 3: Use the total extra spending to find April wheat spending

The total extra spending in May compared to April is ₹ 150.
This extra ₹ 150 comes from the price increase on both rice and wheat.

$\text{Extra on Rice}+\text{Extra on Wheat}=150$

$90+\text{Extra on Wheat}=150$

$\text{Extra on Wheat}=150-90=\text{₹ 60}$

Step 4: Find April wheat spending (W)

The wheat price increased by 12%, so the extra spending on wheat equals 12% of the April wheat spend (W).

$\frac{12}{100}\times W=60$

$W=\frac{60\times 100}{12}=\text{₹ 500}$

So John spent ₹ 500 on wheat in April.

Step 5: Calculate May wheat spending

In May, the wheat price is 12% higher, so John's wheat spending increases by 12%.

$\text{May Wheat Spending}=500\times \frac{112}{100}=500\times 1.12=\text{₹ 560}$

Verification:
Total April spending = ₹ 450 + ₹ 500 = ₹ 950
Total May spending = ₹ 540 + ₹ 560 = ₹ 1100
Difference = ₹ 1100 − ₹ 950 = ₹ 150 ✓

Therefore, John spent ₹ 560 on wheat in May.