What Deficiency does the below rebus represent?

VIT_MIN

There is a brick of gold and a brick of iron in a boat (both 10-inch blocks), if they are both dropped into the water which will make the water level higher?

Before Mount Everest was discovered, what was the highest mountain in the world?

I went to the bookshop and spent one-half of the money that was in my purse.

When I came out, I found that I had as many cents as I had dollars and half as many dollars as I had cents when I went in. Find the money in my purse when I entered the store.

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

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

How many times do a clock's hands overlap in a day ?

I am white when I am dirty, and black when I am clean. What am I?