Answer:
<u>112 children</u>
<u>180 adults</u>
Step-by-step explanation:
Let the number of adults = A
Let the number of children = C
A + C =292
4A + 1.5C = 888. solve for A, C
A = 292 - C
4[292 - C] + 1.5C = 888
1,168 - 4C + 1.5C = 888
-2.5C = - 280
C = -280 / -2.5
C = 112 - Number of children
292 - 112 = 180 - Number of adults
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
4x-7: "seven less than" means you're going to subtract it from the upcoming value, which is "the product of four and a number". "a number" refers to an unknown variable, which I chose to be x. So put it all together and you get 4x-7
