Answer:
System of equations:
20x + 30y = 650
x + y = 25
Time underwater = 10 hours
Time at the surface = 15 hours
Step-by-step explanation:
Let x = time underwater at 20 km/h.
Let y = time on the surface at 30 km/h.
speed = distance/time
distance = speed * time
distance underwater: 20x
distance on the surface: 30y
total distance: 650
20x + 30y = 650
total time: x + y
total time: 25
x + y = 25
20x + 30y = 650
x + y = 25
20x + 30y = 650
-20x - 20y = -500
--------------------------------
10y = 150
y = 15
x + y = 25
x + 15 = 25
x = 10
You can’t .................
The title of the work introduced is Rechnung nach der lenge/auff den Linien und Feder.
<h3>What are mathematical operations?</h3>
In mathematics, an operation is a function that takes zero or more input values to a well-defined output value.
Adam Riese developed the signs + and - as mathematical operations and the title of the work introduced is Rechnung nach der lenge/auff den Linien und Feder.
Learn more about operations on:
brainly.com/question/20408113
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73<span>÷12-17
Difference means subtraction. </span>
Use your calculator ........................
