हिंदी

The product of three numbers in A.P. is 224, and the largest number is 7 times the smallest. Find the numbers

Advertisements
Advertisements

प्रश्न

The product of three numbers in A.P. is 224, and the largest number is 7 times the smallest. Find the numbers

योग
Advertisements

उत्तर

Let the three numbers in A.P. be a – d, a, a + d (d > 0)

Now (a – d) a (a + d) = 224

⇒ a (a2 – d2) = 224  .....(1)

Now, since the largest number is 7 times the smallest

i.e., a + d = 7(a – d)

Therefore, d = `(3"a")/4`

Substituting this value of d in (1), we get

`a(a^2 - (9a^2)/16)` = 224

a = 8

And d = `(3a)/4 = 3/4 xx 8` = 6

Hence, the three numbers are 2, 8, 14.

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 9: Sequences and Series - Solved Examples [पृष्ठ १५२]

APPEARS IN

एनसीईआरटी एक्झांप्लर Mathematics [English] Class 11
अध्याय 9 Sequences and Series
Solved Examples | Q 6 | पृष्ठ १५२

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

How many terms of the A.P.  -6 , `-11/2` , -5... are needed to give the sum –25?


If the sum of n terms of an A.P. is (pn qn2), where p and q are constants, find the common difference.


A man starts repaying a loan as first installment of Rs. 100. If he increases the installment by Rs 5 every month, what amount he will pay in the 30th installment?


If the sum of three numbers in A.P., is 24 and their product is 440, find the numbers.


Find the sum of all numbers between 200 and 400 which are divisible by 7.


A farmer buys a used tractor for Rs 12000. He pays Rs 6000 cash and agrees to pay the balance in annual installments of Rs 500 plus 12% interest on the unpaid amount. How much will be the tractor cost him?


The Fibonacci sequence is defined by a1 = 1 = a2, an = an − 1 + an − 2 for n > 2

Find `(""^an +1)/(""^an")` for n = 1, 2, 3, 4, 5.

 


Which term of the A.P. 84, 80, 76, ... is 0?


Which term of the sequence 12 + 8i, 11 + 6i, 10 + 4i, ... is purely imaginary?


The 10th and 18th terms of an A.P. are 41 and 73 respectively. Find 26th term.


If the nth term of the A.P. 9, 7, 5, ... is same as the nth term of the A.P. 15, 12, 9, ... find n.


Three numbers are in A.P. If the sum of these numbers be 27 and the product 648, find the numbers.


Find the four numbers in A.P., whose sum is 50 and in which the greatest number is 4 times the least.


If the sum of three numbers in A.P. is 24 and their product is 440, find the numbers.


Find the sum of the following arithmetic progression :

 (x − y)2, (x2 + y2), (x + y)2, ... to n terms


Find the sum of the following serie:

 2 + 5 + 8 + ... + 182


Find the sum of first n odd natural numbers.


Find the sum of all integers between 50 and 500 which are divisible by 7.


Find the sum of all even integers between 101 and 999.


The third term of an A.P. is 7 and the seventh term exceeds three times the third term by 2. Find the first term, the common difference and the sum of first 20 terms.


If Sn = n2 p and Sm = m2 p, m ≠ n, in an A.P., prove that Sp = p3.


Find an A.P. in which the sum of any number of terms is always three times the squared number of these terms.


If a, b, c is in A.P., then show that:

 a2 (b + c), b2 (c + a), c2 (a + b) are also in A.P.


If \[a\left( \frac{1}{b} + \frac{1}{c} \right), b\left( \frac{1}{c} + \frac{1}{a} \right), c\left( \frac{1}{a} + \frac{1}{b} \right)\] are in A.P., prove that abc are in A.P.


A man saved Rs 16500 in ten years. In each year after the first he saved Rs 100 more than he did in the receding year. How much did he save in the first year?


A man saves Rs 32 during the first year. Rs 36 in the second year and in this way he increases his savings by Rs 4 every year. Find in what time his saving will be Rs 200.


A manufacturer of radio sets produced 600 units in the third year and 700 units in the seventh year. Assuming that the product increases uniformly by a fixed number every year, find (i) the production in the first year (ii) the total product in 7 years and (iii) the product in the 10th year.


There are 25 trees at equal distances of 5 metres in a line with a well, the distance of the well from the nearest tree being 10 metres. A gardener waters all the trees separately starting from the well and he returns to the well after watering each tree to get water for the next. Find the total distance the gardener will cover in order to water all the trees.


If the sum of n terms of an AP is 2n2 + 3n, then write its nth term.


Sum of all two digit numbers which when divided by 4 yield unity as remainder is


If a1, a2, a3, .... an are in A.P. with common difference d, then the sum of the series sin d [cosec a1cosec a2 + cosec a1 cosec a3 + .... + cosec an − 1 cosec an] is


Write the quadratic equation the arithmetic and geometric means of whose roots are Aand G respectively. 


If abc are in G.P. and a1/b1/y = c1/z, then xyz are in


If for an arithmetic progression, 9 times nineth term is equal to 13 times thirteenth term, then value of twenty second term is ____________.


Find the sum of first 24 terms of the A.P. a1, a2, a3, ... if it is known that a1 + a5 + a10 + a15 + a20 + a24 = 225.


A man accepts a position with an initial salary of Rs 5200 per month. It is understood that he will receive an automatic increase of Rs 320 in the very next month and each month thereafter. Find his salary for the tenth month


If the sum of p terms of an A.P. is q and the sum of q terms is p, show that the sum of p + q terms is – (p + q). Also, find the sum of first p – q terms (p > q).


Let Sn denote the sum of the first n terms of an A.P. If S2n = 3Sn then S3n: Sn is equal to ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×