So yes, I'm retaking Algebra 2 over the summer because I got a C+ during the actual school year. I blame the teacher, since right now I have a 96.4 average with a different one, but let's ignore the part where I try to salvage my intellectual pride. A tank can be filled using pipes A, B, or both. It takes pipe A, running alone, 18 hours to fill the tank. It takes both pipes, running together, 9.9 hours to fill the tank. How long does it take pipe B, running alone, to fill the tank? And if anyone could do either one of these, I would really appreciate it... The speed of a stream is 4 km/h. A boat travels 6 km upstream in the same time it takes to travel 12 km downstream. What is the speed of the boat in still water. I know they're pretty simple compared to the stuff that comes later, but I didn't do too hot in the class for a reason.
It takes pipe B 19.8181 hours to fill the tank. Please note that I did a bit worse than you when I took Algebra 2 =P
OMG I'M A GENIUSSSS I was gonna say 2km/h just cuz it looked right along with the other numbers. But since I didn't actually do the math, I didn't want to post it. no big deal or anything, I wouldn't worry about it if I were you.
Yeah, I kinda need to know how you figured out those answers, seeing as how I have a test tomorrow... And according to the back of the book, #2 is 12 km/h, so yeah...
DUHDUHDUHDUH! Here's the work for the second one. STUPID ME! D: 6 km × 1 hour/(b-4 km) = 12 km × (1 hour/(b+4 km) 6/(b-4) hours = 12/(b+4) hours 6(b+4) = 12(b-4) 6b + 24 = 12b - 48 72 = 6b b = 12 The boat's speed in still water is 12 km/hour.
And after looking at the first one, I made a rookie mistake there. It takes pipe A, running alone, 18 hours to fill the tank. It takes both pipes, running together, 9.9 hours to fill the tank. How long does it take pipe B, running alone, to fill the tank? ----- A DATA: time = 18 hrs/job ; rate = 1/18 jobs/hr -------------------------------------------- A/B DATA: time = 9.9 hrs/job ; rate = 1/9.9 job/hr -------------------------------------------- B DATA: time = x hrs/job ; rate = 1/x job/hr ---------------------------------------- Equation: rate + rate = together rate 1/18 + 1/x = 1/9.9 --- 9.9x + 9.9*18 = 18x 8.1x = 9.9*18 x = 22 hrs (time required by the B pipe to fill the tank) Give me some slack, schools out. xD
Well you'd have to look for it I guess. When was the last time you saw it? And you've checked it's not in any of your pockets right?
If you're serious, what you want to do is draw a third line to make a right triangle. It should be the reciprocal of one of the lines if I remember correctly. Then find the distance of two of the sides of the triangle, and then use trig to find the angle needed. BUT, the two equations you gave me don't form an acute angle, they form an angle of 120 degrees, an obtuse angle. So technically you're question is obsolete or I'm a complete retard.
