Advertisements
Advertisements
प्रश्न
The first three terms of an AP are respectively (3y – 1), (3y + 5) and (5y + 1), find the value of y .
Advertisements
उत्तर
The terms (3y -1), (3y +5) and (5y +1) are in AP.
∴ (3 y + 5) - (3y-1) = (5y+1) - (3y+5)
⇒ 3y + 5-3y +1 = 5y + 1-3y-5
⇒6 = 2y-4
⇒ 2y = 10
⇒ y = 5
Hence, the value of y is 5.
APPEARS IN
संबंधित प्रश्न
If the mth term of an A.P. is 1/n and the nth term is 1/m, show that the sum of mn terms is (mn + 1)
In an AP given a3 = 15, S10 = 125, find d and a10.
Find the sum of all 3 - digit natural numbers which are divisible by 13.
Find the sum of all natural numbers between 250 and 1000 which are divisible by 9.
The sum of three consecutive terms of an AP is 21 and the sum of the squares of these terms is 165. Find these terms
What is the sum of first n terms of the AP a, 3a, 5a, …..
If an denotes the nth term of the AP 2, 7, 12, 17, … find the value of (a30 - a20 ).
Find the sum of first n even natural numbers.
Choose the correct alternative answer for the following question .
First four terms of an A.P. are ....., whose first term is –2 and common difference is –2.
Find the sum \[7 + 10\frac{1}{2} + 14 + . . . + 84\]
Which term of the sequence 114, 109, 104, ... is the first negative term?
Write the value of x for which 2x, x + 10 and 3x + 2 are in A.P.
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 =
If Sn denote the sum of the first n terms of an A.P. If S2n = 3Sn, then S3n : Sn is equal to
An article can be bought by paying Rs. 28,000 at once or by making 12 monthly installments. If the first installment paid is Rs. 3,000 and every other installment is Rs. 100 less than the previous one, find:
- amount of installments paid in the 9th month.
- total amount paid in the installment scheme.
Q.7
For an A.P., If t1 = 1 and tn = 149 then find Sn.
Activitry :- Here t1= 1, tn = 149, Sn = ?
Sn = `"n"/2 (square + square)`
= `"n"/2 xx square`
= `square` n, where n = 75
The famous mathematician associated with finding the sum of the first 100 natural numbers is ______.
Jaspal Singh repays his total loan of Rs. 118000 by paying every month starting with the first instalment of Rs. 1000. If he increases the instalment by Rs. 100 every month, what amount will be paid by him in the 30th instalment? What amount of loan does he still have to pay after the 30th instalment?
Find the middle term of the AP. 95, 86, 77, ........, – 247.
