Re: 21, 22 of SC 2006 Test
Q. 21
4+5 (the total of the ratios) = 9
27 (the total of the notes)/ 9 = 3
3x4=12
3x5=15
Therefore there are 12 $10 notes and 15 $20 notes, which gives:
12x10=$120
15x20=$300
Total value= $420
Q. 22
2^2 x 2^3 = 2^5 (you add the powers when multiplying, and subtract when dividing)
That's the theory (answer rather) behind it, someone might want to explain it better to fully answer the question.
Q. 23
After talking to my friend I found there are two ways to do this. First the easy way which I didn't think of:
x= double the number that is added to x in M (in this case 4, which gives 8)
7
y= same as above 6
You can do this because the mid-point values are half of what the other values are.
Longer more structured way is following the mid-point formula:
M(x,y) = ((x1+x2)/2 , (y1+y2)/2)
M(3,4) = ((-1+x2)/2 , (2+y2)/2))
So you're working out what will add together then divide to give 3 then same for y to get 4.
