I don't understand this!!!

Question

If rstv=1 and stuv=0, which of the followin must be true?

a.r<1
b.s<1
c.t>1/2
d.u=0
e.v=0

for the second set to be zero, one of the letters has to equal zero. In the first set, none are zero. What new letter is in the second set?

I don't understand your question

for the second set to be zero, one of the letters has to equal zero. In the first set, none are zero. What new letter is in the second set?

u?