Find the 42term of ap if 15term is 79 and26 term is 157

1.	Find the 42term of ap if 15term is 79 and26 term is 157
Answer» Solution :- We have, a 15th term = 79 a 26th term = 157 a 42th term = ?By Formula a nth term = a + (n -1)d a + 25d = 157 ------------(1) a + 14d = 79 ------------(2) Subtract (2) from (1),we get 11d = 142 .°.d =142/11 d = 12.9 Putting d = 12.9 in equation (2) ,we get a = -- 165.6 Put the value of a and d in a 42th term a 42th term = a + 41d =>a 42th term = 363.3

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