You'd say that although that seems correct, since there's a 50/50 chance of each outcome, it doesn't necessarily guarantee that it will ALWAYS be 50/50. However, her guess has the highest probability of occurring, or in other words, its more likely that it'll be somewhere close to 240 rather than in the 100's or 300's.
The Anwser to 29-40 is -11
You cannot eliminate x and end up with two different equations.
5x+3y=9.. B
2x-4=40...A
Solve A for x.
2x - 4 = 40
2x = 40 + 4
2x = 44
x = 44/2
x = 22
The only thing I can think of doing is to plug 22 into B.
5(22) + 2y = 9
110 + 2y = 9...This leads to an answer for y.
No two NEW EQUATIONS is possible.
2y = 9 - 110
2y = -101
y = -101/2
Check your question again.
This is just for the first page
1: 9
2: 9.2
3. 1/4
4. 10.2
5. 99
6. 2 1/7
7. 15.9
8. 125
9. 200
10. |15| and |-15|
11. <
12. =
13. <
14. >
15a. boat A is 33 and boat B is 25
15b. boat B is closer
16. -12, -9, 0, |-7|, 12, |-13|
17. -17, -15, |-16|, |-18|, |-20|, 22
18. 0
19. 4
20. -3