Advertisements
Advertisements
Question
What is the 5th term form the end of the AP 2, 7, 12, …., 47?
Advertisements
Solution
The given AP is 2, 7, 12, ..., 47.
Let us re-write the given AP in reverse order i.e. 47, 42, .., 12, 7, 2.
Now, the 5th term from the end of the given AP is equal to the 5th term from beginning ofthe AP 47, 42,.... ,12, 7, 2.
Consider the AP 47, 42,..., 12, 7, 2.
Here, a = 47 and d = 42 – 47 = –5
5th term of this AP
= 47 + (5 – 1) × (–5)
= 47 – 20
= 27
Hence, the 5th term from the end of the given AP is 27.
APPEARS IN
RELATED QUESTIONS
If the 3rd and the 9th terms of an AP are 4 and –8 respectively, which term of this AP is zero?
How many terms of the AP. 9, 17, 25 … must be taken to give a sum of 636?
Find the four numbers in A.P., whose sum is 50 and in which the greatest number is 4 times the least.
Find the sum of first n terms of an AP whose nth term is (5 - 6n). Hence, find the sum of its first 20 terms.
The sum of the first n terms of an AP is (3n2+6n) . Find the nth term and the 15th term of this AP.
The fourth term of an A.P. is 11. The sum of the fifth and seventh terms of the A.P. is 34. Find its common difference.
Fill up the boxes and find out the number of terms in the A.P.
1,3,5,....,149 .
Here a = 1 , d =b`[ ], t_n = 149`
tn = a + (n-1) d
∴ 149 =`[ ] ∴149 = 2n - [ ]`
∴ n =`[ ]`
The sum of third and seventh term of an A. P. is 6 and their product is 8. Find the first term and the common difference of the A. P.
The sum of the first n terms of an A.P. is 3n2 + 6n. Find the nth term of this A.P.
The first and last terms of an A.P. are 1 and 11. If the sum of its terms is 36, then the number of terms will be
If the sum of n terms of an A.P. is 2n2 + 5n, then its nth term is
The number of terms of the A.P. 3, 7, 11, 15, ... to be taken so that the sum is 406 is
If k, 2k − 1 and 2k + 1 are three consecutive terms of an A.P., the value of k is
Q.6
Q.19
If the second term and the fourth term of an A.P. are 12 and 20 respectively, then find the sum of first 25 terms:
Find the value of x, when in the A.P. given below 2 + 6 + 10 + ... + x = 1800.
For an A.P., If t1 = 1 and tn = 149 then find Sn.
Activitry :- Here t1= 1, tn = 149, Sn = ?
Sn = `"n"/2 (square + square)`
= `"n"/2 xx square`
= `square` n, where n = 75
If the first term of an AP is –5 and the common difference is 2, then the sum of the first 6 terms is ______.
If the first term of an A.P. is 5, the last term is 15 and the sum of first n terms is 30, then find the value of n.
