Question

Emanuel has 745 pictures in his phone.His memory is getting full so he starts deleting 20 pictures every day.Define each variable and write an algebraic expression to describe the number of pictures left on his phone after any given number of days.

Answer 1

One variable is the amount of days. Lets call the amount of days D. Another variable is the amount of pictures left. Lets call this p. In this case, since Emanuel is deleting 20 pictures a day, and he has 745 picture to start with, the equation would be 745- 20D=p. 

Answer 2

`745-20d`

Explanation:

Let d represent number of days.

We have been given that Emanuel starts deleting 20 pictures every day. The number of pictures deleted in d days will be
`20d`.

We have been given that Emanuel has 745 pictures in his phone. The number of pictures left after d days would be initial number of pictures minus number of pictures deleted in d days.

`745-20d`

Therefore, the expression
`745-20d` represents number of pictures left on Emanuel's phone after any given number of days.