What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

If,

A + B = C
D - C = A
E - B = C

Based on the above equations, find out the answer for:

D + F = ?

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?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

Using eight eights and addition only, can you make 1000?

Solve the equation in the image by looking at the pattern closely.

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Replace the question mark with the number below given a simple math problem.

There are six people in a family namely M, N, O, P, Q and R.

R and O are brother and sister.

N is the brother of Q's husband.
P is the father of M and grandfather of R.

How many male members are in the family?