Solution:

18 * 12 / 6 + 4

Solution:

1611

Explanation:
The number on the right side is formed as (sum of digits of the 1st number)(number1/number2)
example,
24 $ 6 = 64 (2+4 = 6) (24/6 = 4)
35 $ 5 = 87 (3+5=8) (35/5 = 7)
63 $ 7 = 99 (6+3 =9) (63/7 =9)

Simillarly,
88 $ 8 = (8+8 = 16) (88/8 = 11)

Solution:

    35997
+ 284508
========
    320505
========

Solution:

15/4 hours

Explanation:
Let us say they drive for "t" hours and initial fuel is "f"
Amount of fuel consumed by Fernando car is ft/4
Amount of fuel consumed by Sebastian car is ft/5

As per given condition,
f - ft/5 = 4(f-ft/4)
t = 15/4 hours

Solution:

168
12 14
6 2 7
3 2 1 7

Explanation:
If we multiply two numbers below, we will get the number above it.
like. 3*2 of the last row =>6 of the third row.

Solution:

Since Dean is at the 15th position from both ends, it means that there are 14 people before him and 14 people after him.

14 + 14 = 28
Counting him as well in the row, the total no. of people = 28 + 1 = 29.

Solution:

In the first deal, Sam made a profit of $250.
In the second deal, Sam made a profit of $250 again.

Therefore, he earned a total profit of $500.

Solution:

The remaining time is 15 minutes.

Since, 1/5 part of the time you have spent is left, the total time is 6 parts.

The total time is 90 minutes. 1/6 of 90 = 15.

Therefore, 15 minutes are remaining.

Solution:

There can be three cases for this question.
1) X and Y are present in the same row.
In this case, Y will be the tallest in the row => Y is taller than X.

2) X and Y are present in the same column.
In this case, X will be the shortest of the column => Y is taller than X.

3) X and Y are present in different rows and different columns. Suppose that the child standing in X’s column and Y's row is Z. Then:
Y is taller than Z and Z is taller than X => Y is taller than X.

Therefore, in any of the above cases, Y is taller than X.

Solution:

In the given statement, the letters represent their equivalent position in the alphabets.
A + A = 1 + 1 = 2 = B
B + B = 2 + 2 = 4 = D
A + D = 1 + 4 = 5 = E

Hence,
B + D + E = 2 + 4 + 5 = 11 = K