Advertisements
Advertisements
प्रश्न
If a = 6 and d = 10, then find S10
Advertisements
उत्तर
a = 6 and d = 10 ......[Given]
Since Sn = `"n"/2[2"a" + ("n" - 1)"d"]`,
S10 = `10/2 [2(6) + (10 - 1)(10)]`
= 5[12 + 9 (10)]
= 5(12 + 90)
= 5(102)
= 510
संबंधित प्रश्न
How many terms of the A.P. 65, 60, 55, .... be taken so that their sum is zero?
Find the sum given below:
34 + 32 + 30 + ... + 10
Find the sum of the first 11 terms of the A.P : 2, 6, 10, 14, ...
Find the sum of 28 terms of an A.P. whose nth term is 8n – 5.
The first and the last terms of an A.P. are 34 and 700 respectively. If the common difference is 18, how many terms are there and what is their sum?
Write the next term for the AP` sqrt( 8), sqrt(18), sqrt(32),.........`
The sum of the first n terms in an AP is `( (3"n"^2)/2 +(5"n")/2)`. Find the nth term and the 25th term.
How many terms of the AP 21, 18, 15, … must be added to get the sum 0?
Write an A.P. whose first term is a and the common difference is d in the following.
a = 10, d = 5
Two A.P.’s are given 9, 7, 5, ... and 24, 21, 18, ... If nth term of both the progressions are equal then find the value of n and nth term.
Rs 1000 is invested at 10 percent simple interest. Check at the end of every year if the total interest amount is in A.P. If this is an A.P. then find interest amount after 20 years. For this complete the following activity.
Write the value of x for which 2x, x + 10 and 3x + 2 are in A.P.
The number of terms of the A.P. 3, 7, 11, 15, ... to be taken so that the sum is 406 is
Q.2
In a Arithmetic Progression (A.P.) the fourth and sixth terms are 8 and 14 respectively. Find that:
(i) first term
(ii) common difference
(iii) sum of the first 20 terms.
The sum of the first three numbers in an Arithmetic Progression is 18. If the product of the first and the third term is 5 times the common difference, find the three numbers.
How many terms of the A.P. 24, 21, 18, … must be taken so that the sum is 78? Explain the double answer.
Which term of the AP: –2, –7, –12,... will be –77? Find the sum of this AP upto the term –77.
How many terms of the AP: –15, –13, –11,... are needed to make the sum –55? Explain the reason for double answer.
Three numbers in A.P. have the sum of 30. What is its middle term?
