Mathematics
Grade10
Easy
Question
Find the 30th term of the Arithmetic Sequences 10 , 7 , 4……..
- 77
- -77
- -87
- 87
Hint:
The given question is about arithmetic progression. Arithmetic progression is a sequence of numbers where, the difference between two consecutive terms is constant. We are given the sequence. We are asked to find the 30th term. We will find the common difference first.
The correct answer is: -77
The given sequence is 10, 7, 4, …
The first term of the progression is a1 = 10.
Common difference is the fixed difference between the consecutive numbers of the sequence. We have to add the common difference to the preceding term, to get the next term. It can be negative or positive number. It can also have value zero.
The common difference is d = 7 – 10
d = -3
The formula for nth term of a arithmetic progression is given as follows:
an = a + (n – 1)d
We will substitute n = 30 to find the 30th term.
a30 = 10 + (30 – 1)(-3)
= 10 + (29) (-3)
= 10 – 87
= -77
So, the 30th term is -77.
For such questions, we should know the formula to find any number of the terms.
