yumi2012 wrote:An eccentric casino owner decides that his casino should only use chips in $5 and $7 denominations. Which of the following amount cannot be paid out using these chips?
A. $31
B. $29
C. $26
D. $23
E. $21
To determine the amount that CANNOT be paid out, we'll eliminate the amounts that CAN be paid out.
When we scan the 5 answer choices, we can see that we can eliminate 3 of them almost immediately.
We can pay out $21 using three $7 chips, so ELIMINATE E.
Since $26 is $5 greater than $21, we can pay out $26 using three $7 chips and one $5 chip. ELIMINATE C.
Since $31 is $10 greater than $21, we can pay out $31 using three $7 chips and two $5 chips. ELIMINATE A.
This leaves us with B and D.
We can pay out $29 using two $7 chips, and three $5 chips so ELIMINATE B.
By the process of elimination (POE), the correct answer must be
D
Cheers,
Brent
