SSC CGL 202011)The average of 24 numbers is 56. The average of the first 10 numbers is 71.7 and that of the next 11 numbers is 42. The next three numbers i.e. 22nd, 23rd and 24th are in the ratio, \({1\over2}:{1\over3}:{5\over12}\) . What is the average of the 22nd and 24th numbers?
60.5
22nd number : 23rd number : 24th number = \({1\over2}:{1\over3}:{5\over12}\) = 6 : 4 : 5
According to the question, \(10\times 71.7+11\times 42+6k+4k+5k= 24\times 56\) ; ⇒ k = 11 ;
Required average = \({6k+5k\over2}= {11\times11\over2}= 60.5\)