Answer:
The fraction will increase by 100%
Step-by-step explanation:
Say the fraction is x/y. The question is telling us to decrease x by 20% (i.e. 0.8x) and to decrease y by 60% (i.e. 0.4y):
You can see that by applying these changes, the new fraction is actually double the old fraction (i.e. will increase by 100%).
50%
x=1x so 1-0.6=0.4x
y=1y so 1-0.2=0.8x
0.4x/0.8y
Simplify:
1x/2y= 0.5xy
0.5xy*100=50%
So it decreased by 50%
Answer: 18,20
there is an 86% change
c. how late it is in the evening is a function of the length of time the shutter needs to stay open.