Marcus is going to start saving $20 every month to buy a stereo. His parents gave him $10 for his birthday to
open his savings account.
Exploration:
1.
Write an equation that represents Marcus's savings
account balance x months after he began saving. Let
x= the number of months and y= the savings account
balance.

y = $10 + I

where I = PRT/100

P = $10, R = $20 T = x

Step-by-step explanation:

I represents the Simple Interest formula

P is the Principal or the Money used to start the savings account.

R represents the rate which in this case is $20 let month

T is the time expended which in this case is x

Hope this helps!!

the total estimated nappy use.=10,500,000

step-by-step explanation:

given that on an average the average baby uses 3528 napkins.

in a particular year 2014, the number of births were 299697 in new south wales.

rounding off the number of births to the nearest hundred thousand we have

no of birtsh = 300000

also rounding off the average usage to nearst thousand we get

average use of a baby = 3500

hence total number of nappy estimated to be used = 3500x300000

= 10,500,000

answer is 10,500,000 nappies