Suppose the larger pump alone can empty the tank in L hours, and the smaller pump can finish the job in S hours, then each hour the large pump empties 1/L portion of the tank, and the small pump empties 1/S per hour
Working together for three hours, they empty the whole tank, which is 100% of it, so 3/L+3/S=100%=1
Larger pump can empty the tank in 4 hours less than the smaller one, so L=S-4
replace L: 3/(S-4)+3/S=1
Make the denominator the same to solve for:
3S/[S(S-4)] +3(S-4)/[S(S-4)]=1
(3S+3S-12)/[S(S-4)]=1
(3S+3S-12)=[S(S-4)]
S^2-10s+12=0
use the quadratic formula to solve for S
S is about 8.6
The answer is not whole hour.
Answer:
x = 16
y = 131
Step-by-step explanation:
4x + 2x - 6 = 90
6x = 96
x = 16
16 + 33 + y = 180
49 + y = 180
y = 131
Answer:

Step-by-step explanation:
Let
D(t) = the distance to the safe zone (measured in meters)
t = time (measured in seconds)
<u>Given:</u>
Rachel's rate = 24 meters per second
At
seconds
meters
<u>Find:</u> D(t)
Rachel's rate is the slope of the function D(t). Since the distance is decreasing when the time is increasing, the slope must be negative.
Hence, the function expression is

To find b, substitute
and 

So,
