Question

Difficulty: MediumFraction Multiplication and Division in Context

A communications platoon is upgrading its field radio systems. The unit has a single continuous spool of copper grounding wire that measures 421242 \frac{1}{2} meters in length. Each radio system requires exactly 2562 \frac{5}{6} meters of this wire for a proper ground connection. Calculate the maximum number of complete radio systems the platoon can ground using this spool.

Answer:The platoon can ground a total of 【15】 complete radio systems.

Answer

15
To determine how many complete systems can be grounded, the total length of the wire (421242 \frac{1}{2} meters) must be divided by the length required per system (2562 \frac{5}{6} meters). Converting both to improper fractions gives 852÷176\frac{85}{2} \div \frac{17}{6}. Multiplying by the reciprocal yields 852×617\frac{85}{2} \times \frac{6}{17}, which simplifies to 5×3=155 \times 3 = 15.

Step-by-Step Solution

1
Convert both mixed numbers to improper fractions.
4212=85242 \frac{1}{2} = \frac{85}{2} and 256=1762 \frac{5}{6} = \frac{17}{6}
Multiplication and division of fractions require improper fractions rather than mixed numbers.
2
Set up the division equation.
852÷176\frac{85}{2} \div \frac{17}{6}
To find how many items of a specific size fit into a total quantity, you must divide the total by the size of one item.
3
Rewrite the division problem as multiplication by taking the reciprocal of the divisor.
852×617\frac{85}{2} \times \frac{6}{17}
Dividing by a fraction is mathematically equivalent to multiplying by its reciprocal.
4
Simplify by cross-canceling common factors and multiply.
Divide 8585 by 1717 to get 55. Divide 66 by 22 to get 33. Then, 5×3=155 \times 3 = 15.
Cross-canceling before multiplying keeps the numbers small and manageable without a calculator.

Key Concept

Dividing a total quantity by a fractional size using improper fractions and reciprocal multiplication.
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