Carcass wrote:
p+|k|>|p|+k
Quantity A |
Quantity B |
p |
k |
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
Kudos for
R.A.E Warning: This is a long solution, but there are some key properties/strategies that some students may find usefulUseful properties:
#1: If x is POSITIVE, then |x| = x
#2: If x is NEGATIVE, then |x| = -xFor example, if x = 3, then |x| = |3| = 3 = x
Conversely, if x = -3, then |x| = |-3| = 3 = -(-3) = -x
Okay, first notice that
p and k cannot be equal.
IF it were the case that p = k, then we can replace p with k to get:
k+|k|>|k|+kThis makes no sense. So, we can be sure that p and k are
not equalNow let's examine 4 possible cases:
case i: p is POSITIVE and k is POSITIVE
Applying
property #1, we get:
p+k>p+kThis makes no sense.
p+k=p+kSo,
case i is impossible.
case ii: p is POSITIVE and k is NEGATIVE
Applying
properties #1 and 2, we get:
p+(−k)>p+kSubtract p from both sides of the inequality to get:
−k>kAdd k to both sides to get:
0>2kSince k is NEGATIVE in this case, the inequality
0>2k is true.
So,
case ii is possiblecase iii: p is NEGATIVE and k is POSITIVE
Applying
properties #1 and 2, we get:
p+k>(−p)+kSubtract k from both sides of the inequality to get:
p>−pAdd p to both sides to get:
2p>0Since p is NEGATIVE in this case, the inequality
2p>0 is NOT true.
So,
case iii is impossible.
case iv: p is NEGATIVE and k is NEGATIVE
Applying
property #2, we get:
p+(−k)>(−p)+kAdd p to both sides to get:
2p−k>kAdd k to both sides to get:
2p>2kDivide both sides by 2 to get:
p>kThis tells us that, if p is NEGATIVE and k is NEGATIVE, then
p>kcase iv is possibleAt this point, we can see that there are only two possible cases, and for each case, we can be certain that
p>kAnswer: A
Cheers,
Brent