It will take them 16 days to complete the job
The exercise is basiacally asking for the perimeter of the garden. The perimeter of a rectangle is twice the sum of its dimensions, so we have

Okay so instead of dividing you will cross multiply.
4n(15)=84(5)
60n=420
420/60=7
Answer: n=7
10 years. Bill is 25, his sister is 5, and their mother is 60.
So r+c=42
c=4+r
subsitute c=4+r for r in r+c=42
r+4+r=42
add like terms
2r+4=42
subtract 4 from both sides
2r=38
divide both sides by 2
r=19
rob=19
subsitute r=19 for r in c=4+r
c=19+4
carly=23