i had cards to write, i wrote 1 third of cards on monday, 2 eighths on tuesday, 1 sixth on wednesday and wrote the remaining 27 cards on thursday. how many cards did i write?
number of cards --- x
so ...
x/3 + x/4 + x/6 + 27 = x
times 12
4x + 3x + 2x + 324 = 12x
3x = 324
x = 108
check:
108/3 + 108/4 + 108/6 + 27
= 36+27+18+27
= 108