The sign shows the prices of various school
supplies. Hans bought some notepads and pencils
and spent $9.57. Which equation represents this
situation?
A. 3.88x = 9.57
B.
9.57 - x = y
C.
1.89x + 9.57 = 1.99y
D.) 1.99x + 1.89y = 9.57

(D) 1.99x + 1.89y = 9.57

Step-by-step explanation: The reason is because equation option D states that for every notepad and pencil, x and y he bought, the total of his bill would equal $9.57.

step-by-step explanation: a reaction is first order. if the initial reactant concentration is 0.0200 m, and 25.0 days later the concentration is 6.25 x 10-4 m, then its half-life is: