A = 4.2+0.6 = 4.8 per day;

(2) Remaining days =1755-45 =1710m.

Days Less Used =1710 ÷ (4.8+4.2)-1710 ÷ (4.8+4.2+0.2+0.3) =190.

(1) Assuming that B repairs X meters every day, there are:

5×(x+x+0.6)= 45；

10x = 42；

x = 4.2

So B repairs 4.2 meters every day, and A repairs 4.8 meters every day;

(2) If the number of days used less is X days, there are:

( 1755-45)÷(4.2+4.8)-x =( 1755-45)÷(4.2+4.8+0.2+0.3)；

x = 10；

So it took 10 days less.