Q1) If p, s, and t are positive prime numbers, what is the value of p^3s^3t^3?
(1) p^3st=728
(2) t=13
(1) p^3st=728
(2) t=13
ON MY WAY TO HBS......
1) First, break 728 into its prime factors.
728 = 2 * 2 * 2 * 7 * 13
Then, make it equal to the 'pst' formula.
p^3*s*t = 2*2*2*7*13
Therefore,
p = 2
s*t = 7*13
and
p^3=8
(s*t)^3 = s^3*t^3 = 7^3*13^3
Sufficient, since we can find p^3s^3t^3.
2) t=13 tells us nothing about p ands, therefore this is insufficient.
Answer is A.
