Please check my answer and let me know if it is right or not.
25+.32m(800)=281
28+.30(400)=148
70+40+2(30+.29)=830 +.29m
(1) Yes
(2) Yes
(3) Hmm how did you arrive with your answer, because I'm getting,
= 70 + 40 + 2(30 + .29)
= 110 + 2(30.29)
= 110 + 60.58
= 170.58
or perhaps there is typo or missing info? And I'm also curious with your use of 'm' units.