serio walked to and from school on 3/5 of the days in one month. He got a ride to school on 7/8 of the remaining days. On the remaining school day that month he stayed home with a cold. How many school days were there that month?

Question

serio walked to and from school on 3/5 of the days in one month.  He got a ride to school on 7/8 of the remaining days.  On the remaining school day that month he stayed home with a cold.  How many school days were there that month?

Steve · Answer

3/5 x + (7/8)(2/5)x + 1 = x x = ?

Reiny · Answer

number of school days ----- x
walking to school = (3/5)x = 3x/5
getting ride = (7/8)(2x/5) = 7x/20

walking plus riding = 3x/5 + 7x/20 = 19x/20
staying home --- 1 day

3x/5 + 7x/20 + 1 = x
19x/20 + 1 = x
times 20
19x + 20 = 20x
x = 20