Problema Solution
twin brothers, bill and bobby, can mow their grandparents lawn together in 105 minutes. Billy could mow the lawn by himself in 20 minutes less time that it would take bobby. how long would it take bobby to mow the lawn by himself?
Answer provided by our tutors
Let 'x' and 'y' stand for bill and bobby respectively and 't' stand for the time it takes bobby to mow the lawn. We will use the general equation: (work)=(rate)(time). From the given, we can write:
(x+y)105=1
x(t-20)=1
yt=1
Rates are in min/yard. Solving for t, we get:
t=220.48min