Let x = Parent's age now y = son's age now
Then, x-5 = parent's age five years ago
y-5 = son's age five years ago
So, x-5 = 5(y-5)
Simplify to get x - 5y = -20
Parent's age 8 years from now = x+8
Son's age 8 years from now = y+8
So, x+8 = 3(y+8)
Simplifying, we have x - 3y = 16
We have the system of equations: x - 5y = -20
x - 3y = 16
Subtract the equations to obtain -2y = -36
y = 18
x = 70
Parent is 70 years old and the son is 18 years old.
Answer:
Step-by-step explanation:
Complete question
Required
Solve for x
We have:
Collect like terms
Multiply through by
Make x the subject
Here you go, and please mark brainliest :)
Answer:
v ≈ 8.5 km/h
Step-by-step explanation:
Since the diameter of the wheel is 3 m the radius will be r = 1.5 m.
Use the radius of the water wheel to find it's circumference C:
[set r = 1.5 m]
⇒
⇒ m
One revolution of the water wheel corresponds to meters so the angular velocity 15 rmp (revolutions per minute) corresponds to:
= /min
Using this result, the speed of the river in kilometers per hour will be:
× ×
⇒
⇒ ≈ km/h