Question

CMR:1/3+ 1/30+ 1/32+ 1/35+ 1/45+ 1/47+1/50 <1/2

Answer 1

1/3+1/30+1/32+1/35+1/45 +1/47 +1/50 < 7/14

1/3+1/30+1/32+1/35+1/45 +1/47 +1/50 <1/14 +1/14 +1/14 +1/14 +1/14 +1/14 +1/14 

dù 1/3>1/14 nhưng :1/30<1/14 1/32<1/14 ;1/35<1/14 ;1/45<1/14 ;1/47<1/14 ;1/50<1/14 

nên: 1/3+1/30+1/32+1/35+1/45 +1/47 +1/50 < 1/2