Quote:
If d represents the hundredths digit and e represents the thousandths digit in the decimal .4de, what is the value of this decimal rounded to the nearest tenth?
(1) d – e is equal to a positive perfect square.
(2) sqrt(d) > e^2
C?
Number = 0.4 if d<=5
Number = 0.5 if d>5
Our aim is to see if d is lesser than or equal to 5.
(1) d – e is equal to a positive perfect square.
combination for positive perfect square for < 10 pairs are:
9 = 9-0
4 = 9-5, 8-4, 7-3, 6-2, 5-1, 4-0
1 = 9-8, 8-7, ...., 2-1
We cannot decide. d may be 2 or 9
(2) sqrt(d) > e^2
d > e^4
e has to be 1, since e=2 will make d>16 not possible.
if e=1, e^4 = 1 and d can be 2 or 9
Insufficient
Together,
e=1 from (2)
d should be 5 or 2 from (1)
In both cases, d<=5 and hence the value of the given decimal is 0.4