Answer:
Sum of the sequence = 132.
Step-by-step explanation:
The given sequence is 153, 139, 125,.......n terms.
Sum of the arithmetic sequence will be
S = n/2[2a + (n -1)d]
where n = number of terms
a = first term of the sequence
d = common difference
for the given sequence
a = 153
n = 22
d = 139 - 153 = -14
Therefore sum of 22 terms of the sequence will be
S = (22/2)[2×153 - (22-1)14]
= 11×[306 - 21×14]
= 11×[306 - 294] = 11×12 = 132
Sum of 22 terms of this sequence is 132.