Experts and above only

need for my friend for his 6th grade math. i have my own homework to work on right now, but i really want him to be able to get .

1. This must be greater than or equal to 0 (there can't be any negatives!)
8 - .5t ≥ 0.
8 ≥ .5t 
t ≤ 16
D. 

2. 4(2x-1) = 2x + 35
8x - 4 = 2x + 35
6x = 39
x = 6.5
H.

3. c = .8(x-15) = .8x-12
A.

4. m = number of marble cupcakes
s = number of strawberry shortcake cupcakes

6m + 8.5s = 391
m = 1/2s
6(.5s)+8.5s = 391
11.5s = 391
s = 34
m = 17
F.

5. B
6. Use substitution
2x + 3x = 10
5x = 10
x = 2

7.  (sorry I'm not sure!)

8. G
9. L = number of balls
B = number of bats
L + B = 100
B = 100 - L
4.5L+20B = 822
4.5L + 20(100-L) = 822
4.5L -20L + 2000 = 822
1178 = 15.5L
L = 76

10. J

The answer should be c.