Advertisements
Advertisements
Question
The sum of the 2nd and the 7th terms of an AP is 30. If its 15th term is 1 less than twice its 8th term, find the AP.
Solution
Solution:
The sum of 2nd and the 7th terms of an AP is 30
(a + d) + (a + 6 d) = 30
2a + 7d = 30 ..................(i)
Now,
15th term is 1 less than twice the 8th term
(a + 14d) = 2(a + 7d) -1
a + 14d = 2a + 14d -1
a = 1............................ (ii)
Substituting the values in (i)
2x1 + 7d = 30
d = 4............................ (iii)
Hence, the terms in AP are …. a, a+d, a+2d, a+3d….
AP : 1,5,9 ……
APPEARS IN
RELATED QUESTIONS
The 10th term of an A.P. is 52 and 16th term is 82. Find the 32nd term and the general term
Write first four terms of the A.P. when the first term a and the common differenced are given as follows:
a = 10, d = 10
Write the next two terms of A.P. whose first term is 3 and the common difference is 4.
Find n if the nth term of the following A.P. is 68
5, 8, 11, 14, ..........
If 10 times the 10th term of an A.P. is equal to 15 times the 15th term, show that 25th term of the A.P. is zero.
Write the expression an- ak for the A.P. a, a + d, a + 2d, ... Hence, find the common difference of the A.P. for which
20th term is 10 more than the 18th term.
Show that (a − b)2, (a2 + b2) and (a + b)2 are in A.P.
Find the common difference of the A.P. and write the next two terms \[0, \frac{1}{4}, \frac{1}{2}, \frac{3}{4}, . . . \]
Find the first term and common difference of the Arithmetic Progressions whose nth term is given below
tn = 4 – 7n
The sum of the squares of five consecutive natural numbers is 1455. Find the numbers.
