10 minutes : 8 problems
x minutes : 60 problems
10 * 60/8 = 150/2 = 75 minutes for 60 problems
The answer
according to the figure, we can solve this problem only by applying sines rule:
that is
sinA/a = sinB/b = sinC /c
As we observe, sin A /54 = sin B/27 = sin C/ c, and c = AB
besides, sinC > sinB > sinA , so the only answer possible is
<span>27 < AB < 81</span>
Answer: x = 1.28 or -1.28
35x -10y=-120
10x +10y= 30
45x=-90
x=-2
5(-2)+5y=15
-10+5y=15
5y=25
y=5
(-2,5): the answer is b
