Casual apparel giant Gap Inc on Thursday showed more signs of its recovery as it posted a 20 per cent surge in April same-store sales on the back of revamped merchandise and more focused marketing. The California-based operator of around 4,240 stores said in a news release that total sales for the four weeks ended May 3 jumped 22 per cent to $1.2 billion from $962 million in the year-ago period.