Answer:
I'd say 8 h given the provided nformation
9(n+3)=7n-3
1) distribute 9 into (n+3)
9n+27=7n-3
2) subtract 7n on both sides
2n+27=-3
3) subtract 27 on both sides
2n=-30
4) divide by 2
n=-15
7 hours b 228 km in 3 hours
If the first question mark is 3 then the next is 13 than the next still 13 and the right one 26 and then lastly x is equally to 2
Or
3x+9+10x=33
13x+9=33
13x=26
X=2