52 < R+5+R mai mic sau egal 54

Răspuns :

53-5=48
48:2=24
52<24+5+24
52<25+5+25
52<26+5+26
ETC
52 < R+5+R ≤ 54
52 < 2R+5 ≤ 54
52-5 < 2R ≤ 54-5
47<2R≤49
47:2<2R:2≤49:2

23,5< R≤24,5