-
A positive number x has the property that x% of x is 4. What is x?
(A) 2
(B) 4
(C) 10
(D) 20
2005 AMC 10 B, Problem #2— “Convert x% to a fraction.”
- Solution (D) We have
x
· x = 4,
100
so
x2 = 400.
Because x > 0, it follows that x = 20.
Difficulty: Easy
NCTM Standard: Algebra Standard: Understand patterns, relations, and functions
Mathworld.com Classification:
Number Theory > Arithmetic > Fractions > Percent
27
(E) 40