Answer:
It depends on your career but the important types are counting, addition, subtraction, multiplication and division.
I can't see the picture it is too small
Selling price of app per user = $10 per month
Total no. of user in first month = 10
To tal no. of user added per month = 7
We have to find how much money is earned in one year
So the formula is n/2 * (2a +(n-1)d)
Here we have n = 12 which is total no. of months
a = 100 , which is money earned in one month
d = 70 , which is increase in money earned per month
So money earned in a year comes out to be 5820
Cow- 1/3 = 12/36
goose- 1/12 = 3/36
goat= 2/9 = 8/36
12 + 3 + 8 = 23/36
23/36 is the fraction of the snack left
Joe: 8 songs in 10 minutes = 8/10 = 0.8 songs per minute
Jasmine: 12 songs in 15 minutes = 12/15 = 0.8 songs per minute
they are downloading at the same speed