The problem of the fox the chicken and the grain
We always used to struggle with this type of puzzle but it is just a case of getting the order correct.
Give it a go and see if you can solve the problem of the fox the chicken and the grain.
You have a fox, a chicken and a sack of grain. You must cross a river with only one of them at a time. If you leave the fox with the chicken the fox will eat the chicken, if you leave the chicken with the grain the chicken will eat the grain. How can you get all three across safely?
Take the chicken over first. Go back and bring the grain next, but instead of leaving the chicken with the grain, come back with the chicken. Leave the chicken on the first side and take the fox with you. Leave it on the other side with the grain. Finally, go back over and get the chicken and bring it over.