Răspuns :
1/5(75)=75:5*1
=15*1
=15.............=> 3/5(75)=75:5*3
=15*3
=45
1/5(280)=280:5*1
=56*1
=56..........=> 3/5(280)=280:5*3
=56*3
=168
1/5(1430)=1430:5*1
=286*1
=286.......=> 3/5(1430)=1430:5*3
=286*3
=858
1/5(20455)=20455:5*1
=4091*1
=4091............=> 3/5(20455)=20455:5*3
=4091*3
=12273
=15*1
=15.............=> 3/5(75)=75:5*3
=15*3
=45
1/5(280)=280:5*1
=56*1
=56..........=> 3/5(280)=280:5*3
=56*3
=168
1/5(1430)=1430:5*1
=286*1
=286.......=> 3/5(1430)=1430:5*3
=286*3
=858
1/5(20455)=20455:5*1
=4091*1
=4091............=> 3/5(20455)=20455:5*3
=4091*3
=12273