3 numbers x y and z are to bea randomly chosen between 0 and 1.

A What is the probability that X + y + z will be less than 1?

B What is the probability that both x+ y<1 and 1<x+a

Try your best and...
Thanks alot!

2 answers

A)The volume of the pyramid which is bounded by the planes x=0, y=0, z=0, x+y+z=1 (where 0<=x,y,z<=1 and x+y+z<=1) is equal 1/6.
The volume of the cube 0<=x,y,z<=1 is 1.
Geometric probability P=(1/6)/1=1/6.
B)P(x+y<1)=1/2,
1<x+a what is a?
Thank you and sorry I typed it wrong "a" is y