Sequences and Series - Online Test
Q1. Sum of all 2 digit odd numbers is
Answer : Option D
Explaination / Solution:
Q2.
The number of terms common to the two A.P.s 2 , 5 , 8 , 11 … , 98 and 3 , 8, 13 , 18, 23 , … , 198
Answer : Option C
Explaination / Solution:
Q3. The values of x for which the solutions of the equation cos θ=x,θ≥0 form an A.P. are
Answer : Option C
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Q4. If a∈R, then the roots of the equation tan x = a are in G.P for what values of a
Answer : Option C
Explaination / Solution:
Q5. The values of ‘a’ for which the roots of the equation sin θ = a in A.P. are
Answer : Option A
Explaination / Solution:
Q6. The sum of first four terms of an A. P. is 56 and sum of last four terms is 112. If the first term is 11, then the number of terms is
Answer : Option B
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Q7. The ratio of the to the ( n –1)th mean between 1 and 31, when n arithmetic means are inserted between them, is 5 : 9. The value of n is
Answer : Option B
Explaination / Solution:
Q8. The sum of first n terms of the series 1 – 1 + 1 – 1 + … is
Answer : Option C
Explaination / Solution:
Q9. If a, b, c are in A. P. as well as in G.P.; then
Answer : Option B
Explaination / Solution:
a,b,c are in A.P, .......................(i)
a,b,c are in G.P, .............................(ii)
from (i) and (ii), we get
using a=c in (ii)
so, a=b=c
Q10. The 20th term of the series 2×4+4×6+6×8+... is
Answer : Option C
Explaination / Solution:
here,
