GMAT Word Problems: Which of the following expresses…
Question
State X has 77 acres designated as wilderness, which is 0.0003 percent of its total acreage. Which of the following expresses the total acreage of State X?
- 3(10^4)(77)
- 3(10^6)(77)
- ((10^2)(77))/3
- ((10^4)(77))/3
- ((10^6)(77))/3
Topics: word problems, percentages, conversions
Solution
Step 1
We first choose a variable for the total acreage of State X.
T = total acreage of State X
Step 2
We translate the statement "77 acres designated as wilderness, which is 0.0003 percent of its total acreage" into an equation.
77 = (0.0003)/100 × T
Step 3
We isolate the total acreage by dividing both sides by the percentage coefficient.
T = 77/((0.0003)/100)
Step 4
We simplify the percentage fraction in the denominator to scientific notation.
(0.0003)/100 = 0.000003 0.000003 = 3 × 10^(-6)
Step 5
We then simplify and express the total acreage in scientific notation.
T = 77/(3×10^(-6)) = 77/3 × 10^6
Answer
((10^6)(77))/3 (E)
