Advertisements
Advertisements
प्रश्न
Find the sum of all numbers from 50 to 350 which are divisible by 6. Hence find the 15th term of that A.P.
Advertisements
उत्तर
The numbers from 50 to 350 which are divisible by 6 are 54, 60, 66, ……, 348.
∴ First term =a=t1= 54, d= 6 and tn= 348
tn = a+(n-1)d
∴348 = 54+(n-1)6
∴294 = (n-1)6
∴49 = n-1
∴n = 50
`S_n= n/2(t_1+t_n)`
∴S50= `50/2(54+348)`
=25*402
=10050
t15 = 54+14(6)= 54+84 = 138
Thus, the sum of all numbers from 50 to 350,which are divisible by6, is 10050 and the 15th term of this A.P. is 138.
APPEARS IN
संबंधित प्रश्न
Find the sum given below:
34 + 32 + 30 + ... + 10
In an AP Given a12 = 37, d = 3, find a and S12.
Find the sum of first 51 terms of an AP whose second and third terms are 14 and 18 respectively.
Show that the sum of all odd integers between 1 and 1000 which are divisible by 3 is 83667.
Find the sum of first 20 terms of the sequence whose nth term is `a_n = An + B`
If the numbers a, 9, b, 25 from an AP, find a and b.
Find the first term and common difference for the A.P.
0.6, 0.9, 1.2,1.5,...
If the common differences of an A.P. is 3, then a20 − a15 is
Find the sum of the first 15 terms of each of the following sequences having nth term as xn = 6 − n .
Let there be an A.P. with first term 'a', common difference 'd'. If an denotes in nth term and Sn the sum of first n terms, find.
Write 5th term from the end of the A.P. 3, 5, 7, 9, ..., 201.
The common difference of an A.P., the sum of whose n terms is Sn, is
The given terms are 2k + 1, 3k + 3 and 5k − 1. find AP.
Mrs. Gupta repays her total loan of Rs. 1,18,000 by paying installments every month. If the installments for the first month is Rs. 1,000 and it increases by Rs. 100 every month, What amount will she pays as the 30th installments of loan? What amount of loan she still has to pay after the 30th installment?
Q.5
Q.16
The sum of the first 2n terms of the AP: 2, 5, 8, …. is equal to sum of the first n terms of the AP: 57, 59, 61, … then n is equal to ______.
The students of a school decided to beautify the school on the Annual Day by fixing colourful flags on the straight passage of the school. They have 27 flags to be fixed at intervals of every 2 m. The flags are stored at the position of the middle most flag. Ruchi was given the responsibility of placing the flags. Ruchi kept her books where the flags were stored. She could carry only one flag at a time. How much distance did she cover in completing this job and returning back to collect her books? What is the maximum distance she travelled carrying a flag?
In an A.P., the sum of first n terms is `n/2 (3n + 5)`. Find the 25th term of the A.P.
