on the first day of every month Katie gets 450 phones she repairs 10 phones every day how many phones does she have left to repair at the end of the 11 day of the month

340 phones

Step-by-step explanation:

Make an expression

She repairs 10 phones each day, d.

Each day she repairs 10 phones, it is 10 phones off the total number (450) she has to repair, so we can subtract 10d from 450.

450-10d

We want to find how many she has left after 11 days, so we can substitute 11 in for d

450-10 (11)

Multiply

450-110

340

She will still have 340 phones left to repair