Determine the A.P. whose 4th term is 18 and the difference of 9th Term from the 15th term is 30.
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Answered by
18
Given:
a4 = 18 & a15 - a9 = 30
a4 = a + (4-1)d
[an = a + ( n- 1) d]
a4 = a +3d
18 = a+3d ……………….(1)
a15 - a9 = 30
a+(15-1)d - [a+(9 -1)d= 30
a + 14 d - [ a +8d ] = 30
a +14d - a - 8d = 30
14d - 8d = 30
6 d = 30
d = 30 /6
d = 5
Put the value of d in eq 1
18 = a+3d
18 = a + 3(5)
18 = a +15
18 -15 = a
3 = a
a = 3
On putting the values of a and d in general form of an AP.
a, a + d, a+2d , a+3d ,......
3, (3+5), (3+2×5), (3+3×5).....
3, 8 , 13, 18……
Hence, the A.P are = 3, 8 , 13, 18……
HOPE THIS WILL HELP YOU.....
a4 = 18 & a15 - a9 = 30
a4 = a + (4-1)d
[an = a + ( n- 1) d]
a4 = a +3d
18 = a+3d ……………….(1)
a15 - a9 = 30
a+(15-1)d - [a+(9 -1)d= 30
a + 14 d - [ a +8d ] = 30
a +14d - a - 8d = 30
14d - 8d = 30
6 d = 30
d = 30 /6
d = 5
Put the value of d in eq 1
18 = a+3d
18 = a + 3(5)
18 = a +15
18 -15 = a
3 = a
a = 3
On putting the values of a and d in general form of an AP.
a, a + d, a+2d , a+3d ,......
3, (3+5), (3+2×5), (3+3×5).....
3, 8 , 13, 18……
Hence, the A.P are = 3, 8 , 13, 18……
HOPE THIS WILL HELP YOU.....
Answered by
3
Hey..!!
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Your Answer -
3,8,13,18,23.....
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I Hope It's help you....!!!
__________
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Your Answer -
3,8,13,18,23.....
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I Hope It's help you....!!!
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