Very interesting question!
Let's try to get something that would work for just 5 for now.
Any of these numbers would leave a remainder of 1 when divided by just 5:
6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61, 66, 71, 76, 81, 86, ...
Notice that they all look like 5*(something) + 1. Basically, they are all multiples of 5 plus 1.
Let's see what would work for just 8:
9, 17, 25, 33, 41, 49, 57, 65, 73, 81, 89, ...
Are there any matches... AHA! It's 81. This is the lowest positive integer greater than 1 that follows the rule for both 5 and 8.
Answer:
<h3>The surface area in square meters that Darren has to paint is

</h3><h3>∴

</h3>
Step-by-step explanation:
Given that Darren is painting a wooden block is a rectangular prism
Its length is 12 cm ,width is 9 cm and height is 5 cm
<h3>To find the surface area in square meters that Darren has to paint :</h3>
Let l be the length, w be the width and h be the height
Then l=12 cm , w=9 cm and h=5 cm
The formula for the Surface area is
A=2(lw+wh+hl) square units
Substitute the values in formula we get,
A=2(12(9)+9(5)+5(12))
=2(108+45+60)
=2(213)
=426
<h3>∴

</h3><h3>∴ the surface area in square meters that Darren has to paint is

</h3>
3/x=5/y multiply both sides by y
3y/x=5 divide both sides by 3
y/x=5/3