Math, asked by rahulgupta100008, 1 year ago

solve 24th question¡!!!!(!!!?¿?????

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Answered by rajkumar981
1
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Answered by siddhartharao77
1
Given that the age of youngest boy was 8 years and the ages of rest of participants are having a common difference of 4 months. if the sum of ages of all the participants is 168 years.

Let a be the first term and d be the common difference and sn be the sum.

Given first term a = 8 years.

Common difference d = 4 months = 4/12 years

                                                          = 1/3 years.


Sn = 168 years.



We know thst sum of n terms of an AP sn = n/2(2a + (n - 1) * d)

                                                                 168 = n/2(2(8) + (n - 1) * 1/3)

                                                                 168 * 2 = n(16 + (n - 1)/3)

                                                                 336 = n(48 + n - 1)/3

                                                                 336 * 3 = n(47 + n)

                                                                 1008 = 47n + n^2

                                                                 n^2 + 47n - 1008 = 0

                                                                 n^2 + 63n - 16n - 1008 = 0

                                                                 n(n + 63) - 16(n - 63) = 0

                                                                 (n + 63)(n - 16) = 0

                                                                 n = -63 (or) n = 16.


Since n value cannot be negative, so n = 16.

 
Therefore the age of the eldest participant = a + (16 - 1) * d

                                                                         = a + 15d

                                                                         = 8 + 15 * 1/3

                                                                         = 8 + 5

                                                                         = 13.




Therefore the age of the eldest participant in the painting competition = 13 years.



Hope this helps!                                                       

siddhartharao77: If possible brainliest it. Thanks.
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