phoenixio wrote:
As a bicycle salesperson, Norman earns a fixed salary of $20 per week plus $6 per bicycle for the first three bicycles he sells, $12 per bicycle for the next three bicycles he sells, and $18 per bicycle for every bicycle sold after the first six. In Week 2, Norman earned more than twice as much as he did in Week 1. If he sold x bicycles in Week 1 and y bicycles in Week 2, which of the following statements must be true? Indicate all that apply
A) x < 5
B) y > x
C) y > 3
I'd create a version of a "growth table" to show possible earnings.
Bikes sold: Earnings
0: $20
1: $26
2: $32
3: $38
4: $50
5: $62
6: $74
7: $92
8: $110
.
.
.Now check the three statements:
A) x < 5
This need not be true.
Norman could have sold 6 bikes in the first week (x = 6) and then sold 1000 bikes in the second week (y = 1000)
ELIMINATE A
B) y > x
This must be true. If, in week 2, Norman earned more than twice as much as he did in Week 1, then he must have sold more bikes in the second week than in the first week.
So, y MUST be greater than x
B is TRUE
C) y > 3
Norman's minimum earnings is $20 (if he sells 0 bikes)
Even if Norman earns the minimal amount ($20) in week 1, he still must sell 4 or more bikes in week 2 in order to earn more than twice as much as he did in Week 1
So, y MUST be greater than 3
C is TRUE
Answer: B, C