Difficulty: Easy
Correct Answer: 400
Explanation:
Introduction / Context:
Problems with nested fractions require careful reading. “Three-fourths of one-fifth of a number” means multiply the number by both fractions. Mastery of fraction multiplication and equation solving is the key here.
Given Data / Assumptions:
Concept / Approach:
Combine the fractions first, then invert the coefficient to isolate n. Keep fractions exact to avoid rounding errors and convert to integers only at the end if desired.
Step-by-Step Solution:
Compute combined fraction: (3/4)*(1/5) = 3/20.Equation: (3/20)*n = 60.Multiply both sides by 20/3: n = 60 * (20/3).Calculate: 60 * 20 = 1200; 1200 / 3 = 400 → n = 400.
Verification / Alternative check:
Check: one-fifth of 400 is 80; three-fourths of 80 is 60. The statement is satisfied exactly, confirming the solution.
Why Other Options Are Wrong:
Common Pitfalls:
Misreading “of” as addition; multiplying by 4/3 instead of 20/3; arithmetic slips with 60 * 20. Work systematically to avoid mistakes.
Final Answer:
400
Discussion & Comments