Answer:
p - a - c = b
Step-by-step explanation:
p = a + b + c
subtract a and b from both sides to isolate c
p - a - c = a - a + b
+ c - c
First you must find a common denominator. In this case 10 will work. You then multiply the top number by whatever you multiplied the bottom number by. This is shown below:
4/5- 3/10 = 8/10- 3/10
You can now solve this to get 5/10. This answer can then be reduced to 1/2.
-7 + -5
When you add negative, it would be the same as subtracting
Turns into: -7-5
-(7+5) = -12
The solutions is -12
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.
