6. In a residential building, the ratio of man and woman is 5 to 8. In August, there are 30 men and 10 women moving out from the building. After that, the ratio of man and woman in this building is 1 to 2. How many men were there in the building before August 1?

please show work.

1 answer

M/W=5/8

(M-30)/(W-10)=1/2

putting from the first equation M=5W/8
into the second equation

(5W/8-30)2=W-20

solve for W, then go back in the first equation and solve for M