Answer:
Step-by-step explanation:
From equations (1) & (2), we find:
6x - 8 = - 3x +10
Plug x = 2 in equation (1)
y = 6(2)-8 = 12-8 =4
So,

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
Answer: 4 questions
Step-by-step explanation:
16h=10 min
2/3=40 min
Use equation:
1:10=x:40
40=10x
x=40/10
x=4
1.a. 2 hours 41 minutes b. 10 hours 21 minutes
2.a. 3:10pm b. 12:42pm