The answer of the second (#e2.jpg) question is E. But I can't see any problem with D. Can someone help me on this?
- Attachments
-
-
First question --
90 / (v-3) - 90 / (v+3) = 1/2
v^2 = 1089, so v = 33
Downstream = 90 / (33+3) = 90 / 36 = 10 / 4 = 2.5 hours
-----------------------------------------------------------------------------------------
Second question --
xy + z = xy + xz
If z = 0, xy = xy
If x = 1, y + z = y + z
Hence E.
Please note that you cannot choose D as you need both x=1 AND y=0.
D says x=1 (which is ok) OR y=0 (which is not ok by itself as
we can only get z = xz)
