So... We got a homework for bonus points so I can't figure out what to do.
Some passangers enter the bus at the beginning. At the first stop 1/9 of those passangers step out. At second stop no one steps out, but the number of passangers is increased by 3/4 of the number of how many came there anyway. At the third stop, 6/7 of passangers who arrived step out and there are 16 passangers left.
How many passangers entered the bus at the beginning?
I know the answer is 72, don't know how to get it.
Tried: z-1/9z+3/4z-6/7z=16 and z-1/9z+3/4x(z-1/9z)-6/7x(3/4x(z-1/9z)=16
Doesn't work out. FFFUUUUU
You have two variables and two equations, solve for a single variable, plug it into the second equation to solve for the other variable, then take the number value you derived and plug it in to solve for the other variable. In this one, the obvious choice would be to solve for z (you get an equation) then plug that in for z in the second equation. Solve for x ( you get a number) take that value for x and plug it into the second equation then solve for z.
Of course this is all assuming you set up your two equations properly, I didn't bother going over the math.