NumericalEasy1 mark
2(c)
In an Arithmetic Progression (A.P.) the fourth and sixth terms are 8 and 14 respectively. Find the:
first term
Topic: Arithmetic progression
Previous-year question practice database
Answer
Exam answer
For an Arithmetic Progression:
T₄ = a + 3d = 8 ...(1)
T₆ = a + 5d = 14 ...(2)
Subtract (1) from (2):
2d = 6
d = 3
Substitute in (1):
a + 3(3) = 8
a + 9 = 8
a = −1
Answer:
First term = −1.
Explanation
Use Tₙ = a + (n−1)d for the 4th and 6th terms. Their difference gives d = 3, and substituting back gives a = −1.