Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

If 21x = 79x, what is the value of x?

If,

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

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

D + F = ?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

0 0 0 = 6
1 1 1 = 6
2 + 2 + 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

In case you were starting to feel confident, this one was meant for third graders in Vietnam. The answer is 66, but we don't blame you for scratching your head about how they got there.

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

Alex opened 24 presents
Jonah opened 8 presents
Clara opened 1 present

Can you find out how many presents were opened by Candy?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

Bobby and Wilbur decided to take their respective car out of the garage and race. None of them cheated and they both stood at the start time and decided to cover a distance in full throttle. The first to reach the mark was to be declared the winner.

Upon reaching the finishing mark, they found out that Bobby's car was 1.2 times faster than Wilbur's. Now, Wilbur had reached the mark about 1 minute and 30 seconds later than Bobby. Bobby's car reached the mark of 60 MPH on average.

Can you calculate the distance between the starting mark and the final mark with the help of the given data?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?