In the sequence, (1, 2, 3), (4, 5, 6), (7, 8, 9, 10)... of sets, the sum of elements in the 50th set is
62525
65225
56255
55765
A.
62525
First term of each sets are 1, 2, 4, 7, ...
Let S = 1 + 2 + 4 + 7 + ... + Tn
S = 1 + 2 + 4 + Tn
On subtracting, we get
0 = 1 + 1 + 2 + 3 + ... - Tn
Tn = 1 + (1 + 2 + 3 + ... (n - 1)terms
First term of 50th set is 1226, therefore series is 1226, 1227, ...50 terms
If f : are defined by f(x) = 2x + 3 and g(x) = x2 + 7, then the values of x such that g(x) = x2 + 7, then values ofx such that g(f(x)) = 8 are
1, 2
- 1, 2
- 1, - 2
1, - 2