Question

A submarine cruises underwater at 20 km/h and on

the surface at 30 km/h. The submarine travels a.
distance of 650 km in 25 h. A linear system was
created and graphed

Answer 1

System of equations:

20x + 30y = 650

x + y = 25

Time underwater = 10 hours

Time at the surface = 15 hours

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