yes sure, i learned this before so
1. a. make a proportion here, of percentage. 
if you cross multiply and divide you get 90%.
1. b. obviously the empty seats would be 10%.
2. a. proportion again, 
cross multiply then divide you ge 15%
3. 30% in decimal form is 0.3. multiply it then to the total amount, so 0.3 x 15 = 4.5
Answer:
a. 3.5 b. 2.25 c. 47.8 deg
Step-by-step explanation:
Take a common point ( C in this case)
1. Take the difference of the y coordinates from the point vertical to C.
C from D in this case.
2.Take the diff of the x coordinates from the points horizontal to the first.
C from B in this case.
3. Now add the diff to the common point. X to x Y to y.
Let's take an example to illustrate this case:
<span>positive fraction = 2/7
</span>
<span>negative fraction = - 3/5
Now we need to subtract </span><span>- 3/5 from 2/7
Right?
2/7 - (-3/5) = 2/7 + 3/5
here we need to unify the denominators as follows:
the lowest common factor between 7 and 5 is 35
2/7 = 10/35
3/5 = 21/35
Now back to </span><span>2/7 + 3/5:
</span><span><span>2/7 + 3/5 = 10/35 + 21/35 = (10+21)/35 = 31/35
That's it
Hope that helps you</span>
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