## Elementary Technical Mathematics

$16\frac{1}{4}$ hours
Each aircraft searched for $3\frac{1}{4}$ hours. Thus, the total number of hours the 5 search planes searched for the missing aircraft is: $\\=5 \times 3\frac{1}{4} \\=5 \times \frac{4(3)+1}{4} \\=5 \times \frac{13}{4} \\=\frac{5(13)}{4} \\=\frac{65}{4} \\=16\frac{1}{4}$