In an a.p the first term is 2 and if the sumof the first 5 terms is equal to 1/4th of the sum of the next 5 terms then find 20th term ?
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as in question a=2(given)
now,S5=1/4
S5=n/2[2a+(n-1)d]
substituting value,
1/4=5/2[2(2)+(5-1)d]
1/4=5/2[4+4d]
1/4=5/2[2(2+2d)]
1/4=5(2+2d)
1/4=10+10d
1/4-10=10d
now,S5=1/4
S5=n/2[2a+(n-1)d]
substituting value,
1/4=5/2[2(2)+(5-1)d]
1/4=5/2[4+4d]
1/4=5/2[2(2+2d)]
1/4=5(2+2d)
1/4=10+10d
1/4-10=10d
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