What has no start, end, or centre?

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

What does this rebus puzzle means ?

Solve the mathematical equation in the picture below.

Given below is simple addition with a defined pattern pattern:
7 + 7 = 2
8 + 8 = 4
8 + 5 = 1
6 + 9 = 3
10 + 11 = 9

Can you analyze the pattern and find out the answer for:

4 + 9 = ?

A wealthy man lives alone in a small cottage. Being partially handicapped he had everything delivered to his cottage. The mailman was delivering a letter one Thursday when he noticed that the front door was ajar. Through the opening he could see the man's body lying in a pool of dried blood. When a police officer arrived he surveyed the scene. On the porch were two bottles of warm milk, Monday's newspaper, a catalog, flyers, and unopened mail. The police officer suspects it was foul play. Who does he suspect and why?

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