Let a1, a2, …, a30 an A.P., S=
and T=
.If a5 = 27and S−2T=75, then a10is equal to
and T= .If a5 = 27and S−2T=75, then a10is equal toQuestion ID - 56539 | SaraNextGen Top Answer Let a1, a2, …, a30 an A.P., S= and T= .If a5 = 27and S−2T=75, then a10is equal to
Let a1, a2, …, a30 an A.P., S= and T= .If a5 = 27and S−2T=75, then a10is equal to
1 Answer
127 votes
Answer Key / Explanation : (52) -
S = a1 + a2 +…+ a30
S =
S = 15(a1+a30)
=15(a1+a1+29d)
T=a1+a3+…+a29
=(a1)+(a1+2d) +…+(a1+28d)
=15a1+2d(1+2+…+14)
T=15a1+210d
Now use S−2T=75
15(2a1+29d) −2(15a1+210 d)=75
d = 5
Given a5 =27= a1+4d
a1 = 7
Now a10 = a1+9d =7+9
5=52
127 votes
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127