Solution:

only 6

Solution:

4100

some people might guess 5000

Solution:

Steps
1. Monica go from side A to B for approx 59 minutes
2. Lisa then move back to side A for 2 minutes to fool guard. Now guard will think she is coming to side A.
3. then she again move toward B :-)

Solution:

Age

Solution:

There are 3 fruits (1 grapes, 1 apples, and 1 oranges).

Solution:

Through needle, the boy deflated the tires. which make the height of the car reduced and it easily passed through the underpass

Solution:

The word 'wholesome'

Solution:

1

As stated
1=6 => 6=1

Solution:

40

Cost of each alphabet is 5

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 :-)