Advertisements
Advertisements
प्रश्न
Ramkali would need ₹1800 for admission fee and books etc., for her daughter to start going to school from next year. She saved ₹50 in the first month of this year and increased her monthly saving by ₹20. After a year, how much money will she save? Will she be able to fulfil her dream of sending her daughter to school?
Advertisements
उत्तर
Let a be the first term and d be the common difference.
We know that, sum of first n terms = Sn = \[\frac{n}{2}\][2a + (n − 1)d]
According to the question,
Saving of Ramkali in 1 year = ₹50 + ₹70 + ₹90.......
Here, a = 50, d = 70 − 50 = 20 and n = 12.
∴ S12 = \[\frac{12}{2}\][2 × 50 + (12 − 1)20]
= 6[100 + 220]
= 6 × 320
= 1920
Hence, After a year, she will save ₹1920.
Since, required amount for admission is ₹1800 and her savings will be ₹1920.
Thus, yes she will be able to fulfil her dream of sending her daughter to school.
APPEARS IN
संबंधित प्रश्न
Find the sum given below:
`7 + 10 1/2 + 14 + ... + 84`
Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.
A ladder has rungs 25 cm apart. (See figure). The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top. If the top and bottom rungs are 2 `1/2` m apart, what is the length of the wood required for the rungs?
[Hint: number of rungs = `250/25+ 1`]
The sum of three terms of an A.P. is 21 and the product of the first and the third terms exceed the second term by 6, find three terms.
Find the sum of the following arithmetic progressions:
3, 9/2, 6, 15/2, ... to 25 terms
Find the 8th term from the end of the AP 7, 10, 13, ……, 184.
Find the sum of first n even natural numbers.
Find the sum of all multiples of 9 lying between 300 and 700.
Find the first term and common difference for the following A.P.:
5, 1, –3, –7, ...
If `4/5` , a, 2 are three consecutive terms of an A.P., then find the value of a.
Let Sn denote the sum of n terms of an A.P. whose first term is a. If the common difference d is given by d = Sn − kSn−1 + Sn−2, then k =
The 9th term of an A.P. is 449 and 449th term is 9. The term which is equal to zero is
The common difference of the A.P.
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.3
In an A.P. sum of three consecutive terms is 27 and their products is 504. Find the terms. (Assume that three consecutive terms in an A.P. are a – d, a, a + d.)
Find the sum of first 17 terms of an AP whose 4th and 9th terms are –15 and –30 respectively.
Assertion (A): a, b, c are in A.P. if and only if 2b = a + c.
Reason (R): The sum of first n odd natural numbers is n2.
The sum of A.P. 4, 7, 10, 13, ........ upto 20 terms is ______.
