23X+ 16Y=500

X and y are natural numbers X=(500- 16y)÷23.

Y=(500-23x)÷ 16

∴ X= 12 Y= 14

2. Solution: Let the short rope of 3m be X and the long rope of 8m be Y..

3X+8Y= 100

X and y are natural numbers X=( 100-8Y)÷3.

y =( 100-3X)8

∴ X=28 Y=2

3. Solution: Set white chalk as X frame and colored chalk as Y frame.

4X+9Y=58

X and y are natural numbers X=(58-9Y)÷4.

y(58-4X)9

∴X= 10 Y=2

∴4X=40 9Y= 18

I don't know if the answer is right, just look at it yourself!