So u turn the percent into a decimal.
0.10
Now multiply 1200 * 0.10
1200*0.10= 120 ( 120 is the amount that is gonna increase)
So if it says 5 years, than your gonna multiply 120 * 5
120*5 =600
So your gonna add 600 to 1200.
So in five years your gonna be making 1,800.
An easier way would be to use prt
Principle * rate * time
1200 * 0.10* 5
= 600
So now you just add 600 to 1200
= 1800
80%, 1000-200 = 800/1000 or 80%
I would think the value would be .2 cause if you had 100 tosses you would expect 60 value for heads and -40 value for tails. giving you 20/100
The answer is 23° hope it help!