for what value of n are the nth terms of the following two APs the same (a) 13,19,25,.... (b)69,68,67....? also find this term.

Asked by prasadnidhi | 1st Nov, 2010, 12:00: AM

Expert Answer:

For the first AP a = 13, d = 6 for the other AP a' = 69 d' = -1
Thus nth term of first AP
an = a + (n-1)d = 13 + (n-1)(6) = 7 + 6n
an' = a' + (n-1)d' = 69 + (n-1)(-1) = 70-n
7 + 6n = 70 - n
7n = 63
n = 9

Answered by  | 3rd Nov, 2010, 09:23: AM

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