the 15th term of an ap exceeds its 10th term by 15 if its fourth term is 17 then its 21st term is
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Step-by-step explanation:
a15= a10 + 15
a4 = 17
take step - by - step
a15 = a10 + 15
a+14d = a+9d + 15
a - a + 14d - 9d = 15
14d - 9d = 15
5d = 15
d= 15/5
d = 3
take
a4 = 17
a+3d = 17
a + 3 ( 3 ) = 17
a + 9 = 17
a = 17 - 9
a = 8
using nth term
an = a + ( n - 1 ) d
a 21 = 8 + ( 21 - 1 ) 3
a21 = 8 + 20( 3 )
a21 = 8 + 60
a21 = 68
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