Answer:

small cups=30
large cups=40
Step-by-step explanation:
let x be the number of small cups and y the number of large cups.
-Given that 10 more cups than small cups of lemonade were sold:

#Before the 10 more were sold, the number of x and y sold were equal>

The number of small cups sold was 30
#Since, the number of large cups was 10 more, y=x+10=30+10=40
Answer:
The number of possible three-digit phone prefixes that are used to represent a particular geographic area is 640.
Step-by-step explanation:
The phone prefixes used to represent a particular geographic area are a 3 digit code consisting of numbers from 0 to 9.
The prefix code are of the form: <u>x</u> <u>x</u> <u>x</u>
Condition: The first or the second place cannot take values 0 or 1.
Then the first place can be occupied by the remaining 8 digits.
Similarly the second place can also be occupied by the remaining 8 digits.
And the third place can be occupied by any of the 10 digits.
So the number of ways to construct a phone prefix for any area is:

Thus, the number of phone prefixes possible for any area is 640.
The answer is -16 and -5.