A= 52 /1.6 + 52 /6.11 +...+ 52 /26.31
..
=> A= 5.( 5/ 1.6 + 5/ 6.11 +...+ 5 /26.31)
=> A= 5.( 1- 1/6 + 1/6 - 1/11 +...+ 1/26 - 1/31)
=> A= 5.( 1 - 1/31 )
=> A= 5. 30/31 = 150/31 > 1
=>A=52(1/1.6+1/6.11+...+1/26.31)
=>A=25/2(2/1.6+2/6.11+...+2/26.31)
=>A=25/2(1/1-1/6+1/6-1/11+....+1/26-1/31)
=>A=25/2(1+0+0+.....+1/31)
=>A=25/2X34/31
=>A=850/62
=>A=425/31
=>A>1(425>31=>A<1)