Question 290664
OK start with what you know:  Use l for length and w for width
perimeter is the outside distance around the rectangle

So:

Since there are 2 lengths and 2 widths on a rectangle then 
2w + 2l = 250
and we know that length is 5 more than 3 times the width
so: l = 3w +5

Now use substitution:

2w + 2(3w + 5) = 250
solve:

2w + 6w + 10 = 250   subtract 10 from both sides and add the w's together
8w = 240    divide by 8
w = 30

so if w = 30 then length is l = 3W + 5
l = 3(30) + 5
l = 90 +5
l = 95

So your answer is width is 30m and length is 95m

Hope this helps