a man left 1\2 of his estate to his wife, 1\6 to his daughter, and the remainder an amount of $15,000, to his son. How large was the entire estate?

Answer 1

entire estate value ---- x

x - (x/2 + x/6) = 15000
times 6
6x - 3x - x = 90000
2x = 90000
x = 45000

check
wife gets 22500
daughter gets 45000/6 = 7500
leaving 15000 for son
all adds up nicely.