Divide both sides by 5. You get 1/2 or 0.5
The answer is C
This is pretty much a "common sense" question. It'd be best to get rid of the dirty sanitizing water and start fresh; in other words, he should change (throw out) the dirty water and make a fresh sanitizer.
By the way, this is the Math section; next time, please choose a different section more suited to your questions.
LOL...it took me a few seconds to realize what you were attempting to express...which is the fifth root of 13 cubed...
(13^3)^(1/5) rule: (a^b)^c=a^(b*c)
13^(3*1/5)
13^(3/5)
(a) put in t = 3 into the r(t) equation provided. Answer will be in gigameters
(b) Use the value of r(t) found in part (a) in the surface area of a sphere equation. S = 4(pi)r² Answer, S will be in units Gm²
(c) This is saying put the equation r(t) into the equation S(r) to make a new equation S(t) or h(t) as they put it.
h(t) = 4(pi)(1.36t + 0.002)²
(d) Put t = 3 into the new equation. Answer will agree with b
Underscore is that line lowered