Arithmetic Progression (A. P.): A sequence is called arithmetic Progression if the difference of a term and the previous term is always same. Ex: 2,4,6 .... are in A. P. If 'a' is the first term and 'd' is the common difference of an A. P. then the 'n' th term is given by a n =a+(n –1)d Here the terms are a, a+d, a+2d,...... a+(n –1)d Terms of A. P. represented by a 1 , a 2 , a 3 ....., or t 1 , t 2 , t 3 .....,   One mark Questions : Enter your answer in the box 1) Find the sum of all 11 terms of an AP whose middle term is 30 Click here to check answer Answer is 330 In an AP with 11 terms, the middle term is (11+1) / 2 = 6th term ⇒Now a 6 = a+5d =30 S 11 = 11 / 2 [2a+10d] =11(a+5d) = 11× 30 =330 2) If 4 times the 4th term of an AP is equal to 18 times the 18th term, then find the 22nd term. Click here to check answer Answer : The 22nd term of AP is '0' Let 'a' be the 1st term and 'd' be the commo