0.25 times r added to 0.6 times 6
8000+500+20+3
numer of 0's at the end is in accordance to the number of numbers behind the number you are writing
1) 475
2)375
You need to multiply 25 by 27 and you get 675 then to get answer one you need to multiply 10 by 20 to get 200 the take 200 away from 675 to get 475 then do the same thing with the second problem 20x15 which is 300 the take 300 away from 675.
Answer:
Eric's expression is :

and Andrea's is :

In Eric's expression, 20 represents the initial amount of substance with which he has started the experiment.
is the amount of substance left after each time period (in this case, each week).The variable w in this case represents the number of weeks.
Andrea's expression can be written as :

The one outside of parentheses represents the initial amount of the substance. The one inside of parentheses represents 100% of the original amount of the substance. 0.5 represents the 50% of the substance that is lost each time period. The variable w in this case represents the number of weeks.
Answer:
6.3
Step-by-step explanation: