Problem (Algebra):
Let $T=1$. Dennis and Edward each take 48 minutes to mow a lawn, and Shawn takes 24 minutes to mow a lawn. Working together, how many lawns can Dennis, Edward, and Shawn mow in $2 \cdot T$ hours? (For the purposes of this problem, you may assume that after they complete mowing a lawn, they immediately start mowing the next lawn.)

Solution:
Working together, Dennis and Edward take $\frac{48}{2}=24$ minutes to mow a lawn. When the three of them work together, it takes them $\frac{24}{2}=12$ minutes to mow a lawn. Thus they can mow 5 lawns per hour. With $T=1$, they can mow $5 \cdot 2=\mathbf{1 0}$ lawns in 2 hours.

Final answer: 10