arithmetic progression - A girl saves money over a period of 200 weeks. She saves 5p in Week 1, 7p in Week 2, 9p in Week 3, and so on until Week 200. Her weekly savings form an arithmetic sequence.

Krishna (last edited 5 years ago) (Expert, Educator @Qalaxia)

Step 1: Identify the first term in the sequence, call this number a.

Step 2: Calculate the common difference(d) of the sequence.

[NOTE: Then Common difference = Succeeding(a+2d) - Preceding(a+d) term = d]

Step 3: Find the term position ( n )

[EXAMPLE: 2,4,6,8,10….in AP

First term 2, term position (n) = 1

Second term 4, term position (n) = 2........

......... 30th term, term position (n) = 30....... ]

Step 4: Substitute all the values in the arithmetic formula

[FORMULA: Tn = a + (n - 1) d,

where Tn = nth term and a = first term. Here d = common difference, n = term position.]

Step 5: Solve for unknown value.