Can you guys me with the number 11 and 12 ? solve the equations

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25

If johnny ate 5 cans of sugar, but in the kitchen they only had 3. what did johnny eat? (he found a secret stash btw.)

The length of a rectangle is 5 times the width. if the perimeter is to be greater than 36 meters. what are the possible values for the width?