Solution:

For(4) + a + change(delta/change symbol)
= For a change

Solution:

Route(Root symbol) + 66
= Route66

Solution:

This problem can be solved with similar triangles property.
The White triangle is similar to the Red one
Now Ratio of sides is 2:3 (as ratio of areas = ratio of based if the height is same)
Seeking that, White triangle = 9/4 * Yellow triangle = 9/2
Following all the above, the Green region = 5.5 units

Solution:

12

Explanation:
The amount won and lost by both is equal.
Thus 2x = 3(20-x) --- x in the number of times heads came
X = 12

Solution:

On multiplying all the 6 pairs we get (a*b*c*d)^3.
Assuming the missing product is a*b, then amid the 5 given products we see (a*c)*(b*d)=(a*d)*(b*c)
If we look at the numbers clearly 5 is out of the equation because there is nothing to balance it so the only remaining match is 2*6=3*4, so a*b*c*d=2*6=12.
So the product of all 6 pairs should be 12^3, the product of the given 5 is 720, so the missing one is 12/5=2.4

Solution:

Man1 is carrying 5 bags and the Man2 is carrying 7 bags.

Let's assume that the Man1 was carrying M1 bags and the Man2 was carrying M2 bags.
M2 + 1 = 2 * (X-1)
M2 + 1 = 2M1 - 2
M2 = 2M1 - 3

Also,
M2 - 1 = M1 + 1
M2 = M1 + 2

=>
2M1 - 3 = M1 + 2
M1 = 5

=>
M2 = 7

Solution:

48 minutes.

Donald duck's speed = X km/seconds
pool current speed = Y km/seconds

2/(X+Y) = 40
2/(X-Y) = 60

Solving the simultaneous equations gives X = 1/24

Therefore, to cover 2km will take 2/X = 48 seconds

Solution:

Marshall lives in House no.36
Robin lives in House no.4
Barney lives in House no.9
Lily lives in House no.35
Lyndsy lives in House no.24

Solution:

444 + 444 + 44 + 44 + 4 + 4 + 4 + 4 + 4 + 4 = 1000

Solution:

There are 5 Insect-A, 7 Insect-B & 6 Insect-C.

Let 'A' be the number of Insect-A, 'B' be number of Insect-B and 'C' be number of Insect-C.
A+B+C = 18
8A+6B+6C = 118
2B+C = 20
Solving this, A=5, B=7, C=6