SpiralFlex
Well-Known Member
- Joined
- Dec 18, 2010
- Messages
- 6,960
- Gender
- Female
- HSC
- N/A
2 hours and 4 hours. It's a basic quadratic question. I just do not know how to structure it.Is the answer for the third question 39 and 37 minutes?
I remember asking you this question last year in the marathon thread. Or maybe you asked me?Let the volume be T
T/80 = rate of both pipes
Let x be time in minutes
T/(x-120) + T/x = T/80 since it's both pipes working together
2x-120 = x(x-120)/80. Solve for x. x will be the larger solution as one of them will give a negative time value
I dunno. I remember seeing one that looked like that in cambridge yr11 3unit. I remember asking you about a circle question though...I remember asking you this question last year in the marathon thread. Or maybe you asked me?
I didn't considered that, I only tried the odd = even contradiction, thanks Jm.For the other one...
Suppose that log_3 5 = p/q p,q relatively prime
5=3^(p/q)
5^q=3^p, which is impossible if p and q are relatively prime (5^q ends with 5 or 0 and 3^p ends with 3, 9, 7, 1 or 3)
It is in the Cambridge 3 Unit Year 11 book. =DI dunno. I remember seeing one that looked like that in cambridge yr11 3unit. I remember asking you about a circle question though...