Solution:

The woman told him to take out one nut each from the rest of the wheels and use them.

Solution:

2 people

Say 2 helpers are Helper1 & Helper2

Helper1 food Helper2 food McDuck's Food
End of Day 1 : 1 4 4
Now 'A' will head back

End of Day 2 : N/A 2 4
Now 'B' will head back

Now Mr. McDuck have 4 day food :-)

Solution:

Michelangelo juggles the diamonds across while crossing the bridge.

Solution:

It can be down as shown below.

Solution:

888 + 88 + 8 + 8 + 8 = 1000

Solution:

The ball will take infinite bounces before it is stopped. As per the question it will keep on bouncing half way up every time it hits the ground. But gravity will play its part at certain point of time which will make it stop.

Solution:

Numbers of the first cube:
1, 2, 4, 0, 5 and 6.

Numbers on the second cube:
3, 1, 2, 7, 8 and 0.

Now you can pick any date and you will be able to show it using these cubes. Remember that you can always use 6 as 9 by inverting it.

This problem has another solution and we leave it for you to deduce.

Solution:

This can be done if you draw a five pointed star and place the balls on the corners and intersection points. See the figure to understand better.

Solution:

A Spider

Solution:

Since the door is not visible in this picture, the bus is moving in the left direction.

Solution:

The women is a of short stature. She can't reach the upper elevator buttons, but can push is with his umbrella.