arithmetic progression - In the first month after opening, a mobile phone shop sold 280 phones. A model for future trading assumes that sales will increase by x phones per month for the next 35 months,

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

Step 1: Write the sequence from the given data and identify the first term in the sequence, call this number a.

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

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. (Apply the BODMAS rules)