The number of terms in the sequence 20, 25, 30, ……, 150 is:
2017
The number of terms in the sequence 20, 25, 30, ……, 150 is:
- A.
22
- B.
23
- C.
26
- D.
27
Attempted by 4 students.
Show answer & explanation
Correct answer: D
Given sequence:
20, 25, 30, … , 150
Check the pattern:
25 − 20 = 5
30 − 25 = 5
So, this is an Arithmetic Progression (AP).
First term:
a = 20
Common difference:
d = 5
Last term:
aₙ = 150
Formula for nth term of AP:
aₙ = a + (n − 1)d
Substitute the values:
150 = 20 + (n − 1) × 5
150 − 20 = 5(n − 1)
130 = 5(n − 1)
26 = n − 1
n = 27