Data:
Dolphin 1: 200ft
Dolphin2:
30% farther: 200ft+60ft=260ft
-Find the 30% of 200
[tex]200\cdot\frac{30}{100}=60[/tex]Ascende 25 1/2 feet and then descended 40 1/2 feet:
Substract to the initial 260ft the 25 1/2 ft and add 40 1/2:
[tex]260-25\frac{1}{2}+40\frac{1}{2}[/tex]To sum or substract mixed numbers write it as fractions:
[tex]\begin{gathered} 25\frac{1}{2}=\frac{50}{2}+\frac{1}{2}=\frac{51}{2} \\ \\ 40\frac{1}{2}=\frac{80}{2}+\frac{1}{2}=\frac{81}{2} \end{gathered}[/tex]Then You have:
[tex]260-\frac{51}{2}+\frac{81}{2}[/tex]You can also write the 260 as a fraction with the same denominator (2):
[tex]\begin{gathered} \frac{520}{2}-\frac{51}{2}+\frac{81}{2} \\ \\ =\frac{520-51+81}{2}=\frac{550}{2}=275 \end{gathered}[/tex]Then, the dolphin 2 is 275 feet under the water