An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

What is the next number in the series?

15 29 56 108 208 ?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

In the Mexico City area, there are two Houses H1 and H2. Both H1 and H2 have two children each.
In House H1, The boy plays for Mexico Youth academy and the other child plays baseball.
In House H2, The boy Plays soccer for his school in Mexico and they recently have a newborn.

Can you prove that the probability of House-H1 having a girl child is more than that of House-H2?

Three people check into a hotel. They pay $60 for the rent of the room. After they check-in, the manager realize that the rent for the room is $55. So, he gives $5 to the bellboy and asks him to give it to them. The bellboy thinks that it will be difficult for the three people to share $5 among them and seeking the personal benefit, he pockets $2 and gives the remaining $3 to them.

Now, each person paid $20 and got back $1. In this manner, each of them paid just $19 which totals to the amount of $57. The bellboy has $2 with him and adding them, we get $59. So where is the remaining $1?

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?

If two fifty-foot ropes are suspended from a forty-foot ceiling that is twenty feet apart, how much rope will you be able to steal if you have a knife?

Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?

Can you replace the question mark with the correct number?