is it possible to get some tips and tools to solve these "sign" (< = > ) questions?
i dunno if my method can help you but i solved it in two ways.
0 < 1 - (c/d) < 1
the way i looked at this problem was to first simply the equation by subtracting 1 in the middle to both sides:
-1 < -(c/d) < 0
and the given statement is that d is greater than zero, so d must be positive. if we know a variable is positive, you can safely multiply the variable without changing the signs. so i multiplied d to isolate c.
-1(d) < -c < 0(d)
so we get
-d < -c < 0
and then i divided the negative out and switched the signs.
d > c > 0
the above answers statement I. c > 0 is true.
for statement II, i manipulated the above equation by dividing d and i get
1 > c/d > 0
this answers statement II. c/d < 1
the last statement i just tested numbers using the d > c > 0 by using whole numbers and decimals.
the second way i solved this was using bunuel's way.