Rocco has a weekly reading schedule, reading for 4.5 hours per day on some days and 3.5 hours per day on the other days. He reads a total of 25.5 hours in a seven-day week. On how many days does he read for 4.5 hours?

x = days he reads for 4.5 hours = 1 day

y = days he reads for 3.5 hours = 6 days

Step-by-step explanation:

Let

x = days he reads for 4.5 hours

y = days he reads for 3.5 hours

x + y = 7 (1)

4.5x + 3.5y = 25.5 (2)

From (1)

x = 7 - y

Substitute x = 7 - y into (2)

4.5x + 3.5y = 25.5 (2)

4.5(7 - y) + 3.5y = 25.5

31.5 - 4.5y + 3.5y = 25.5

- 4.5y + 3.5y = 25.5 - 31.5

-y = -6

y = 6

Substitute y = 6 into (1)

x + y = 7 (1)

x + 6 = 7

x = 7 - 6

x = 1

x = days he reads for 4.5 hours = 1 day

y = days he reads for 3.5 hours = 6 days

c

step-by-step explanation:

c