What word begins and ends with an E, but has only one letter?

Can you make the below equation true by using any three numbers from "1, 3, 5, 7, 9, 11, 13 and 15"?

( ) + ( ) + ( ) = 30

Can you count the number of quadrilaterals in the picture below?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

Can you count the number of lines in the below picture?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

Which word does the below Plexor means ?

Our product and our sum always give the same answer. Who are we?