Advertisements
Advertisements
प्रश्न
Ramkali saved Rs 5 in the first week of a year and then increased her weekly saving by Rs 1.75. If in the nth week, her week, her weekly savings become Rs 20.75, find n.
Advertisements
उत्तर
Given that,
a = 5
d = 1.75
an = 20.75
n = ?
an = a + (n − 1) d
⇒ 207.50 = 50 + (n - 1) (17.5)
⇒ 207.50 = 50 + 17.5n - 17.5
⇒ 17.5n = 207.50 + 17.5 - 50
⇒ 17.5n = 225 - 50
⇒ 17.5n = 175
⇒ n = `175/17.5`
⇒ n = 10
Hence, n is 10.
APPEARS IN
संबंधित प्रश्न
Find the 9th term from the end (towards the first term) of the A.P. 5, 9, 13, ...., 185
If Sn denotes the sum of first n terms of an A.P., prove that S30 = 3[S20 − S10]
Find the sum of the following APs:
2, 7, 12, ..., to 10 terms.
In an AP given l = 28, S = 144, and there are total 9 terms. Find a.
Find the sum of first 40 positive integers divisible by 6.
Which term of the A.P. 121, 117, 113 … is its first negative term?
[Hint: Find n for an < 0]
The sum of the third and the seventh terms of an AP is 6 and their product is 8. Find the sum of first sixteen terms of the AP.
If the sum of first m terms of an A.P. is the same as the sum of its first n terms, show that the sum of its first (m + n) terms is zero
Determine the A.P. Whose 3rd term is 16 and the 7th term exceeds the 5th term by 12.
Find the sum of 28 terms of an A.P. whose nth term is 8n – 5.
If the 10th term of an AP is 52 and 17th term is 20 more than its 13th term, find the AP
Find the 8th term from the end of the AP 7, 10, 13, ……, 184.
The 7th term of the an AP is -4 and its 13th term is -16. Find the AP.
The 24th term of an AP is twice its 10th term. Show that its 72nd term is 4 times its 15th term.
Find the sum of first n even natural numbers.
If `4/5 `, a, 2 are in AP, find the value of a.
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)
The sum of 5th and 9th terms of an A.P. is 30. If its 25th term is three times its 8th term, find the A.P.
Find the sum of n terms of the series \[\left( 4 - \frac{1}{n} \right) + \left( 4 - \frac{2}{n} \right) + \left( 4 - \frac{3}{n} \right) + . . . . . . . . . .\]
In an A.P., the sum of first ten terms is −150 and the sum of its next ten terms is −550. Find the A.P.
If in an A.P. Sn = n2p and Sm = m2p, where Sr denotes the sum of r terms of the A.P., then Sp is equal to
Q.10
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.
Find S10 if a = 6 and d = 3
Shubhankar invested in a national savings certificate scheme. In the first year he invested ₹ 500, in the second year ₹ 700, in the third year ₹ 900 and so on. Find the total amount that he invested in 12 years
Find the sum of the integers between 100 and 200 that are not divisible by 9.
Find the sum of first 'n' even natural numbers.
Find the sum of first 20 terms of an A.P. whose nth term is given as an = 5 – 2n.
If the last term of an A.P. of 30 terms is 119 and the 8th term from the end (towards the first term) is 91, then find the common difference of the A.P. Hence, find the sum of all the terms of the A.P.
Find the sum of first 16 terms of the A.P. whose nth term is given by an = 5n – 3.
