5. WO APs have the same
common difference. The first
term of one of these is -1 and
that of the other is - 8. Then
the difference between their
10th terms is
9
6
7
5
Answers
Answer:
Step-by-step explanation:
Let the common difference be d.
Tenth term of first AP = -1 + 9d
Tenth term of second AP = -8 + 9d
Difference = (-1+9d)-(-8+9d)
= (-1+9d)+(8-9d)
= 7
Working out:
In this question, we have to find the difference of the 10th terms of two AP whose common difference is same and first terms are -1 and -8 respectively.
First of all, Formula for finding nth term,
So, by using this formula, Let's start solving.....
Let,
- Common difference of 1st and 2nd AP = d
- First term of 1st AP = a1 = -1
- First term of 2nd AP = a'1 = -8
By using above formula, Finding 10th term,
- a10 = a + 9d
- a'10 = a' + 9d
Difference between their 10th terms,
⇛ a10 - a'10 = a + 9d - (a' + 9d)
⇛ a10 - a'10 = a + 9d - a' - 9d
⇛ a10 - a'10 = a - a'
Plugging the values of first terms,
⇛ a10 - a'10 = -1 -(-8)
⇛ a10 - a'10 = -1 + 8 = -7 or 7 (either way)
Here, the common difference between the first terms and the 10th terms were equal as their Common difference is equal for both the APs. So, the difference of 10th terms:
As it given in the options, Option C
And we are done !!