84. Three cars. Three friends are driving in cars along a road in the same direction and at some point in time are positioned relative to each other as follows. Andrews is at some distance behind Brooks, and Carter is at a distance twice that from Andrews to Brooks, ahead of Brooks. Each driver is traveling at a constant speed, and Andrews catches up with Brooks in 7 minutes, and then catches up with Carter 5 minutes later.

How many minutes after Andrews will Brooks catch up with Carter?
84. Brooks will catch up to Carter in \(6 \frac{2}{3}\) min.