Step-by-step explanation:
x+13÷2×2=4×2
x+13=8
x+13-13=8-13
x=8-13
x=-5
Answer: The answer is 51
Step-by-step explanation:
Answer:
in
Step-by-step explanation:
Let x be the side of square.
Length of box=8-2x
Width of box=15-2x
Height of box=x
Volume of box=
Substitute the values then we get
Volume of box=V(x)=


Differentiate w.r.t x









Again differentiate w.r.t x

Substitute x=6

Substitute x=5/3

Hence, the volume is maximum at x=
Therefore, the side of the square ,
in cutout that gives the box the largest possible volume.
New pump:
5 hours = 1 pool
1 hour = 1/5 pool
Old pump:
15h = 1 pool
1h = 1/15 pool
If both work together
1h = 1/5 + 1/15 = 4/15 pool
4/15 pool = 1 hour
1/15 pool = 1/4 hour
15/15 pool = 1/4 x 15
1 pool = 3.75 hours or 3 hours 45 mins