Question

Dolphin 1 dove 200 feet underwater. Dolphin 2 dove 30% farther. After dolphin 2 dove down, it ascended 25 1/2 feet, then descended 40 1/2 feet. How far under the water is the dolphin?

Answer 1

Data:

Dolphin 1: 200ft

Dolphin2:

30% farther: 200ft+60ft=260ft

-Find the 30% of 200

`200\cdot(30)/(100)=60`

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:

`260-25(1)/(2)+40(1)/(2)`

To sum or substract mixed numbers write it as fractions:

`\begin{gathered} 25(1)/(2)=(50)/(2)+(1)/(2)=(51)/(2) \\ \\ 40(1)/(2)=(80)/(2)+(1)/(2)=(81)/(2) \end{gathered}`

Then You have:

`260-(51)/(2)+(81)/(2)`

You can also write the 260 as a fraction with the same denominator (2):

`\begin{gathered} (520)/(2)-(51)/(2)+(81)/(2) \\ \\ =(520-51+81)/(2)=(550)/(2)=275 \end{gathered}`Then, the dolphin 2 is 275 feet under the water