Sequences and Series · Question 49

JEE Main 2025 (Online) 28th January Morning ShiftMCQMedium📈 Topic in 55% papers+4−1

Let Tr be the rth term of an A.P. If for some m, Tm = 125, T25 = 120, and 20 r=125Tr = 13, then 5m r=m2mTr is equal to

Answer

(2) 126

Solution

r=125 Tr = 1320 = 252(T1 + T25)

T1 + T25 = 13250 T1 = 13250 - 120 = 26 - 25500 = 1500

d = T25 - T124 = 25500 - 150024 = 1500

Tr = 1500 + (r - 1) 1500 = r500

Tm = m500 = 125 m = 20

5m r=2040 Tr = 100 1500 r=2040 r = 15 21(20 + 40)2

= 6305 = 126

Answer: (2)

JEE Main 2025 (Online) 28th January Morning Shift

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