Question

For What value of n, are the nth terms of two APs: 63, 65, 67,… and 3, 10, 17,… equal?

Answer 1

1st AP is 63,65,67.......
2nd AP is 3,10,17........

tn of both AP is equal
for 1st AP a = 63 , d= 2
for 2nd AP a= 3 , d= 7

tn of 1st AP = tn of 2nd AP
a + ( n-1) ×d = a + (n-1) × d
63 + (n-1) × 2 = 3 + (n-1) × 7
63 + 2n - 2 = 3 + 7n - 7
63 -2 -3 +7 = 7n - 2n
65 = 5n
n = 65/5
n= 13

Answer 2

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