Remark
The proof is only true if m and n are equal. Make it more general.
m = 2k
n = 2v
m + n = 2k + 2v = 2(k + v).
k and v can be equal but many times they are not. From that simple equation you cannot do anything for sure but divide by 2.
There are 4 combinations
m is divisible by 4 and n is not. The result will not be divisible by 4.
m is not divisible by 4 but n is. The result will not be divisible by 4.
But are divisible by 4 then the sum will be as well. Here's the really odd result
If both are even and not divisible by 4 then their sum is divisible by 4
Well first do you parentheses and the multiply all of your exponets
I think there is no simplified fractions for this number it will be the same -4/17
Since Irina can paint 1 room in 9 hours, that means she paints 1/9 of the room in 1 hour. Her portion of the equation would be 1/9x, with x being the number of hours she works and 1/9 of a room per hour being her speed.
Since Paulo can paint 1 room in 8 hours, that means he paints 1/8 of the room in 1 hour. His portion of the equation would be 1/8x, with x being the number of hours he works and 1/8 of a room per hour being his speed.
The equation would then be 1/9x + 1/8x = 1 (Irina's portion of the room, plus Paulo's portion of the room, equal to one whole room).
Find a common denominator. 72 is the first number that both 9 and 8 divide evenly into. Since 9*8 = 72, we multiply the top of 1/9 by 8 to convert the fraction and get 8/72x. Since 8*9 = 72, we multiply the top of 1/8 by 9 to convert the fractio and get 9/72x. We now have 8/72x+9/72x=1
17/72x=1
Divide both sides by 17/72:
17/72x ÷ 17/72 = 1÷17/72
x=1/1 ÷ 17/72
x=1/1 * 72/17
x=72/17=4.24
Together it should take them 4.24 hours.
