ps

[baller12q]

In a stack of boards at a lumber yard, the 20th board counting from the top of the stack is immediattely below the 16th board counting from the bottom of the stack. How many boards are in the stack?

A. 38
B. 36
C. 35
D. 34
E. 32

[Neo2000]

Counting from top, your 20th board is the 15th board from bottom. Which means there are 14 more boards below the 20th boards. So total number of boards = 34

[quocbao]

The question say 16th, then it should be 35 right ?

[Neo2000]

Nope, that board itself is the 20th board which would mean there are 19boards above it.
Counting from bottom, it is number 15 and with 19boards above it, there are a total of 34boards.