Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

A quarter is one-fourth of a dollar but Mr. John has changed the equation as below :

DOLLAR * 4 = QUARTER

Can you replace each letter with a digit to make the above solution correct?

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?

Can you count the number of squares in the figure below?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

Spot what is wrong here in below Picture?