The value of a_30-a_20 for the AP : 2, 7, 12, …. is *
100
(b) 10
(c) 50
(d) 20
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2
Answer:
a_30-a_20 for the AP : 2, 7, 12, …. is *
100
Answered by
0
50
Step-by-step explanation:
A.P. = 2,7,12,17....
A = first term = 2
Common difference = d = a_2-a_1 =a_3-a_2=7-2=12-7 =5a
2
−a
1
=a
3
−a
2
=7−2=12−7=5
Formula of nth term = a_n=a+(n-1)da
n
=a+(n−1)d
Substitute n = 30
a_{30}=2+(30-1)(5)a
30
=2+(30−1)(5)
a_{30}=147a
30
=147
Substitute n = 20
a_{20}=2+(20-1)(5)a
20
=2+(20−1)(5)
a_{20}=97a
20
=97
So, a_{30}-a_{20}=147-97=50a
30
−a
20
=147−97=50
Hence the value of a_{30}-a_{20}=50a
30
−a
20
=50
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