Algebra
posted by Vice on .
1) Mio can build a large shed in 15 days less than Yuuko can. If they build it together, it would take them 18 days. How long would it take each of them working alone?
M: Y:
2) A sink can be filled by a pipe in 6 minutes but it takes 12 minutes to drain a full sink. If both the pipe and the drain are open, how long will it take to fill the sink?

a)
ratecombined=rateM+rateY
shed/18 = shed/(timeY15) + shed/timeY
Y* (Y15)=18( Y + (y15))
y^215Y=36Y270
y^251Y+270=0
(y45)(Y6)=0
y=45, M=30