I did this two years ago. Hope I can help you.
Answer:
Integers are not closed under the DIVISION operation
Example:
(9 ÷ 2 = 4½)
Answer:
(4, 5 )
Step-by-step explanation:
x + y = 9 → (1)
x - y = - 1 → (2)
adding the 2 equations term by term will eliminate y
2x + 0 = 8
2x = 8 ( divide both sides by 2 )
x = 4
substitute x = 4 into either of the 2 equations and solve for y
substituting into (1)
4 + y = 9 ( subtract 4 from both sides )
y = 5
solution is (4, 5 )
Well, their speeds are (

is Jack's speed, and

is Richard's.

They, together, can paint 12 houses in 35 days. To get a single house, we only have to calculate

which is very close to 3 (a bit below)