Question 266117
It seems as though we don't have enough information here. WE know the following:
(i) {{{B = 1500 + m}}}
(ii) {{{B = 1900 + t}}}
subtracting (i) from (ii) we get
(iii) {{{0 = 400 + t - m}}}
and then
(iv) {{{t = m - 400}}}
we don't know the relation between motor and trailer.