the sum of 2nd and 7th terms of an ap is 30. If it's 15th term is 1 less than twice its 18th term ,find the AP
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hey buddy...
thank you for question....
here's your answer...
t2+t7=30
t15-1=t18
t15+t18=1
t2+t7=30
a+8d+a+(n-1)=30
2[a+8d]=30....(1)
similarly
2[a+32d]=1...(2)
subtract (1) &(2)
a+32d=1
a+8d=30
__________
0+24d=-29
d=-29/24
substitute d=-29/24 in (1)
you'll get a
in such way u can find an A.P
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