Advertisements
Advertisements
प्रश्न
Which term of the AP 21, 18, 15, … is zero?
Advertisements
उत्तर
In the given AP, first term, a = 21and common difference, d = (18-21) = - 3
Let’s its nth term be 0.
Then, Tn = 0
⇒ a +(n-1) d=0
⇒ 21 + (n-1) × (-3) =0
⇒ 24 - 3n = 0
⇒ 3n = 24
⇒ n= 8
Hence, the 8th term of the given AP is 0.
APPEARS IN
संबंधित प्रश्न
Divide 32 into four parts which are in A.P. such that the product of extremes is to the product of means is 7 : 15.
Determine the A.P. whose 3rd term is 16 and the 7th term exceeds the 5th term by 12.
In a potato race, a bucket is placed at the starting point, which is 5 m from the first potato and other potatoes are placed 3 m apart in a straight line. There are ten potatoes in the line.
A competitor starts from the bucket, picks up the nearest potato, runs back with it, drops it in the bucket, runs back to pick up the next potato, runs to the bucket to drop it in, and she continues in the same way until all the potatoes are in the bucket. What is the total distance the competitor has to run?
[Hint: to pick up the first potato and the second potato, the total distance (in metres) run by a competitor is 2 × 5 + 2 ×(5 + 3)]
If the 8th term of an A.P. is 37 and the 15th term is 15 more than the 12th term, find the A.P. Also, find the sum of first 20 terms of A.P.
Find an AP whose 4th term is 9 and the sum of its 6th and 13th terms is 40.
The sum of the first n terms of an AP is (3n2+6n) . Find the nth term and the 15th term of this AP.
In an A.P. 17th term is 7 more than its 10th term. Find the common difference.
Find four consecutive terms in an A.P. whose sum is 12 and sum of 3rd and 4th term is 14.
(Assume the four consecutive terms in A.P. are a – d, a, a + d, a +2d)
If the sum of first p terms of an A.P. is equal to the sum of first q terms then show that the sum of its first (p + q) terms is zero. (p ≠ q)
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.
If Sr denotes the sum of the first r terms of an A.P. Then , S3n: (S2n − Sn) is
Sum of n terms of the series `sqrt2+sqrt8+sqrt18+sqrt32+....` is ______.
x is nth term of the given A.P. an = x find x .
A sum of Rs. 700 is to be paid to give seven cash prizes to the students of a school for their overall academic performance. If the cost of each prize is Rs. 20 less than its preceding prize; find the value of each of the prizes.
A manufacturer of TV sets produces 600 units in the third year and 700 units in the 7th year. Assuming that the production increases uniformly by a fixed number every year, find:
- the production in the first year.
- the production in the 10th year.
- the total production in 7 years.
Q.12
Q.20
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
The ratio of the 11th term to the 18th term of an AP is 2 : 3. Find the ratio of the 5th term to the 21st term, and also the ratio of the sum of the first five terms to the sum of the first 21 terms.
Read the following passage:
|
India is competitive manufacturing location due to the low cost of manpower and strong technical and engineering capabilities contributing to higher quality production runs. The production of TV sets in a factory increases uniformly by a fixed number every year. It produced 16000 sets in 6th year and 22600 in 9th year. |
- In which year, the production is 29,200 sets?
- Find the production in the 8th year.
OR
Find the production in first 3 years. - Find the difference of the production in 7th year and 4th year.
