The answer is 96 min, here is why:
x / 240 + x / 160 = 1
<span>2x + 3x = 480 </span>
<span>5x = 480 </span>
<span>x = 96 min
(</span><span>Drainage rate of first pipe = 480000/240 = 2000 l/min </span>
<span>Drainage rate of second tube = 480000/160 = 3000 l/min </span>
<span>Combined drainage rate = 5000 l/min </span>
<span>Time to drain = 480000/5000 = 96 min. )</span>
I do believe that the answer to your question is 60%
The answer is B
seeing there are 3 way to put it
(a+b)(a-b)=a 2-b 2
(a+b)(a-b)=a^2-b^2
(a+b)(a-b)=a2-b2
and option B matches with the second way to put it i hope this helps
7.465
You could have saved some points and used a calculator! XD