Answer:
The river is 3.15 feet deep.
Step-by-step explanation:
First let's recognize what we need to find: the depth of the river
We know last year the river was 4.2 feet deep, but it dropped 25%. This means we also need to find how much it dropped. To find this, we need to know what 25% of 4.2 is. Write an equation for this.
y = 25% of 4.2
y = 0.25 • 4.2
y = 1.05
This means that the river dropped 1.05 feet. To know its depth now, we need to subtract 1.05 from 4.2. Write an equation for this.
d = 4.2 - 1.05
d = 3.15
The river is 3.15 feet deep.
Hope this helps!
Speed of the east bound cyclist is 12 mph and the speed of west bound cyclist is 15 mph.
<u>Solution:</u>
Let us assume that x is speed of slower eastbound cyclist
So, x+3 will be the speed of faster westbound cyclist
We know that distance is the product of speed and time. That is,

West-bound DATA:
Rate of speed = x+3 mph ; Time = 6 hrs ; distance = 6(x+3) = 6x+18 miles
East-bound DATA:
Rate of speed = x mph ; time = 6 hrs. ; distance = 6x miles
On solving,
Distance apart = 162



So, the rate of speed of the east bound cyclist is 12 mph and the rate of speed of the west bound cyclist will be 
Maybe something like 24/4=6. so sorry if I'm incorrect.