THIS IS CONFUSING!! HELP!?

Question

Bob starts at 4.0 miles west of the school and is running at constant velocity of 6.0 mi/h due east. Mary starts at 3.0 mi east of the school and is running with constant velocity of 5.0 mi/hr due west. How far are the runners from the school when they meet?

(how do they meet when they're going in opposite directions?)

Luke goes to Canada, driving with a constant speed of 89.5 km/hr except for a 22.0 min rest at Starbucks. If Luke's average speed is 77.8 km/hr, how much time is spent on the trip and how far does Luke travel?

(how do you figure out 2 variables?)

Jimmy can run with a speed of 0.10 m/s, and Jimbo can run 20 times as fast. In a race, they both start at the same time, but Jimbo stops to take a nap for 2.0 minutes. Jimmy wins by 20 cm. How long does the race take and what is the length of the race?

PLEASE explain your answers so I can learn from it (instead of just mooching answers) ;)

Answer 1

1. Of course they'll meet. Any two people going towards each other are going in opposite directions. Try drawing a picture and it will make sense.

The distance between them=4+3=7 miles

Their relative speed: 6-(-5)=11 mph

Time it will take them to meet: t=distance/speed=7/11 hour

Distance traveled by Mary by then: d=time*speed=(7/11)*5=35/11 m

Her distance from the school is the distance traveled minus initial distance from school (since at first she was approaching school and then passed it and was running away from it):

D=35/11-3=2/11 mile

Distance traveled by Luke:

(t-22/60)*89.5=t*77.8

11.7*t=(22/60)*89.5=32.8

t=2.8 hours

Now, since we know the time and the speed, we can calculate the distance:

2.8*77.8=218.2 km