Advertisements
Advertisements
प्रश्न
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 =`[ ]`
Advertisements
उत्तर
In the A.P. 1,3,5,....,149
a = 1 , d = 2 , tn = 149
tn = a + (n-1)d
149 = 1+ (n-1) × 2
149 = 1 + 2n -2
149 = 2n - 1
∴ 2n = 150
∴ n = 75
APPEARS IN
संबंधित प्रश्न
In an AP given a = 8, an = 62, Sn = 210, find n and d.
Find the sum of first 15 multiples of 8.
Find the sum of the following arithmetic progressions:
–26, –24, –22,... to 36 terms
If (3y – 1), (3y + 5) and (5y + 1) are three consecutive terms of an AP then find the value of y.
If 18, a, (b – 3) are in AP, then find the value of (2a – b).
How many three-digit natural numbers are divisible by 9?
If the sum of first m terms of an AP is (2m2 + 3m) then what is its second term?
There are 25 rows of seats in an auditorium. The first row is of 20 seats, the second of 22 seats, the third of 24 seats, and so on. How many chairs are there in the 21st row ?
What is the sum of first 10 terms of the A. P. 15,10,5,........?
Find the sum (−5) + (−8)+ (−11) + ... + (−230) .
Sum of n terms of the series `sqrt2+sqrt8+sqrt18+sqrt32+....` is ______.
The sum of n terms of two A.P.'s are in the ratio 5n + 9 : 9n + 6. Then, the ratio of their 18th term is
x is nth term of the given A.P. an = x find x .
Q.2
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 whether 55 is a term of the A.P. 7, 10, 13,... or not. If yes, find which term is it.
The sum of first six terms of an arithmetic progression is 42. The ratio of the 10th term to the 30th term is `(1)/(3)`. Calculate the first and the thirteenth term.
A merchant borrows ₹ 1000 and agrees to repay its interest ₹ 140 with principal in 12 monthly instalments. Each instalment being less than the preceding one by ₹ 10. Find the amount of the first instalment.
The sum of first n terms of the series a, 3a, 5a, …….. is ______.
The sum of all two digit numbers is ______.
