Query Detail : Railways 2019

a man wants to invest Rs. 20220 in bank account of his two sons, whose age were 12 years and 16 years in such a way that they will get equal amount at age of 120 years @ 33(1/3)% per annum compounded annually. find the share of younger son
Anshul,   October 2nd 2019,  
Railways 2019


Let amount of 1st son = x & that of second son = y

here rate = 33(1/3)% = 100/3% 

So x{1+(100/3)/100}^(120-12) = y{1+(100/3)/100}^(120-16)

x{1+(1/3)}^(108) = y{1+(100/3)/100}^(104)

x{4/3}^(108) = y{4/3)^100}^(104)

y/x  = (4/3)^(108-104)

y/x = (4/3)^4 = 256/81

So share of younger son = y  = 256/(256+81)*20220

 = 256/ 337*20220

=  15360