arithmetic progression - The first term of an arithmetic sequence is 30 and the common difference is –1.5. Find the value of the 25th term.

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.