In a mobile recharge plan, data increases by (1.5) GB each day. The data is (2,3.5,5,6.5,\ldots). What is (d)?

Correct answer: (1.5)

The direct answer is option B: \(d=1.5\) GB. In an arithmetic progression, the common difference \(d\) is the fixed amount added to one term to obtain the next term. Here the data values are 2, 3.5, 5, and 6.5. Calculate successive differences: \(3.5-2=1.5\), \(5-3.5=1.5\), and \(6.5-5=1.5\). Since the difference is the same each time, the sequence is an AP and its common difference is 1.5 GB. Option A, 1 GB, is too small and does not turn 2 into 3.5. Option B, 1.5 GB, exactly matches every increase. Option C, 2 GB, would make the next term 4 rather than 3.5. Option D, 3.5 GB, is the second term, not the increase between terms. The word “each day” tells us to compare consecutive days, not to choose a term itself. Memory cue: common difference equals “next term minus previous term”; check it in at least two places.