4. two more than a certain number is 15 less
than twice the number.

17

Step-by-step explanation: Call the certain number x. Two more than x is x+2. 15 less than twice the number is 2x-15.

Setting them equal, x+2=2x-15 and solving gives x=17

$25

step-by-step explanation:

25 - 4.50 = 20.5

20.5 / 2 = 10.25

10.25 + 10 = 20.25

20.25 - 12.50 = 7.75

therefore the answer is $25 as shown as the first number.