Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
I posted 5 queries under the Challenge category, but no reply yet. Anyone here have explanations? Thanks much!
here were my questions: Challenge 25: #6; 12; 18b; 19; 22
#6: my solution seems different from the answer provided.
This is what I got.
2001 : S(1-x/100)
2003: S(1-x/100)^3 = T
S(1-x/100)^3 = T, therefore (1-x/100)^3 = T/S or (1-x/100) = cube root of (T/S)
cost in 2002 therefore is S(1-x/100)^2 or S*(cube root of (T/S))^2
The above checks out if depreciation is 10% for example: 100 in 2000, 90 in 2001, 81 in 2002 and 72.9 in 2003.
Challenge answer is sqrt S*T
12. degrees between 12:24 and 14:36 hour hand.
Can someone please explain the solution to me? I don't understand. I've seen this kind of solution before and not understanding worries me. I got it right though by doing the following and am not sure if the method is right.
At 12, 0degrees.
360/12=30 degrees for minutes hand.
30 degrees = 60 mins therefore 24 mins = ?
(24 * 30)/60 = 12
therefore distance between 2 times is 78-12=66 degrees.
18B. 3 times as many pupils in 2nd as in 1st. Solution says y=3x therefore x cancels out so result can be calculated. If x cancels out, what is the answer?
I got (12.2x+13.1y)/x+y; or 12.2x+13.1*3x/x+3x; = 51.5x/4x;
19. The given equation gets simplified to x+y=10. And this encloses a coordinate plane.
solution: 10^2+10^2= sqrt of 200
BUT what is the assumption in arriving at this solution.
I was at a loss so decided to do (x+y) (x+y) = 10 * 10 = 100 as area, though wasn't sure why I was doing that either! (and it appears to be incorrect anyway)