GATE 2026 Question 61: Perfect competition

The market for torch is perfectly competitive. The market demand function for torch is given by $X^d=\min(400-p,0), p\ge0$, where $p$ is the price of a torch. The market supply for the same good is $X^s=\max\left(0,\left(\dfrac{p}{7}-\dfrac{80}{7}\right)\right), p\ge0$. If a specific tax of 40 is imposed on the purchase of each unit of torch, the corresponding decrease in the consumer surplus is ______ (rounded off to one decimal place)