GMAT Practice Question: Jorge's bank statement showed a balance that was 0.54 dollars greater than what his records...
Question
Jorge's bank statement showed a balance that was 0.54 dollars greater than what his records showed. He discovered that he had written a check for x.yz dollars and had recorded it as x.zy dollars, where each of x, y, and z represents a digit from 0 though 9. Which of the following could be the value of z ?
- 2
- 3
- 4
- 5
- 6
Topics: decimals, digits as unknowns, simultaneous equations
Solution
Step 1
We translate the phrases to set up the difference between the recorded and actual check amounts.
"recorded it as x.zy dollars" - "written a check for x.yz dollars" = 0.54
Step 2
We write each amount in terms of x, y, and z based on place value.
x + z/10 + y/100 - (x + y/10 + z/100) = 0.54
Step 3
We combine like terms to simplify the expression.
9(z - y)/100 = 0.54
Step 4
We clear the denominator and solve for the difference.
9(z - y) = 0.54 100 9(z - y) = 54 z - y = 6
Step 5
Since z and y are digits from 0 to 9 and their difference is 6, z could be 6, 7, 8, or 9, and among the answer choices only 6 appears.
z - y = 6 Possible values for z are 6, 7, 8, or 9 Only 6 appears in the answer choices
Answer
6
