Advertisements
Advertisements
Question
For an given A.P., t7 = 4, d = −4, then a = ______.
Options
6
7
20
28
Advertisements
Solution
For an given A.P., t7 = 4, d = −4, then a = 28.
Explanation:
Given,
t7 = 4
d = −4
Now,
tn = a + (n − 1)d
t7 = a + (7 − 1)d
⇒ 4 = a + 6(−4)
⇒ 4 = a − 24
⇒ a = 4 + 24
⇒ a = 28
RELATED QUESTIONS
The first and the last terms of an AP are 7 and 49 respectively. If sum of all its terms is 420, find its common difference.
Find the sum of the following APs.
`1/15, 1/12, 1/10`, ......, to 11 terms.
Find the sum of first 8 multiples of 3
Find the 12th term from the end of the following arithmetic progressions:
3, 5, 7, 9, ... 201
Find the sum of the following arithmetic progressions:
a + b, a − b, a − 3b, ... to 22 terms
Find the sum of the first 11 terms of the A.P : 2, 6, 10, 14, ...
If 4 times the 4th term of an A.P. is equal to 18 times its 18th term, then find its 22nd term.
The angles of quadrilateral are in whose AP common difference is 10° . Find the angles.
Find the sum of the first n natural numbers.
The A.P. in which 4th term is –15 and 9th term is –30. Find the sum of the first 10 numbers.
If first term of an A.P. is a, second term is b and last term is c, then show that sum of all terms is \[\frac{\left( a + c \right) \left( b + c - 2a \right)}{2\left( b - a \right)}\].
The sum of first n terms of an A.P. is 5n − n2. Find the nth term of this A.P.
Write the nth term of an A.P. the sum of whose n terms is Sn.
If the sum of n terms of an A.P. is 3n2 + 5n then which of its terms is 164?
Let Sn denote the sum of n terms of an A.P. whose first term is a. If the common difference d is given by d = Sn − kSn−1 + Sn−2, then k =
If the first term of an A.P. is 2 and common difference is 4, then the sum of its 40 terms is
The sum of n terms of an A.P. is 3n2 + 5n, then 164 is its
Obtain the sum of the first 56 terms of an A.P. whose 18th and 39th terms are 52 and 148 respectively.
If ₹ 3900 will have to be repaid in 12 monthly instalments such that each instalment being more than the preceding one by ₹ 10, then find the amount of the first and last instalment
Find the sum:
`(a - b)/(a + b) + (3a - 2b)/(a + b) + (5a - 3b)/(a + b) +` ... to 11 terms
