Agroup of four people has to cross a bridge. it is dark, and they have to light the path with a flashlight. no more than two people can cross the bridge simultaneously, and the group has only one flashlight. it takes different time for the people in the group to cross the bridge: chris crosses the bridge in 1 minute, tracy crosses the bridge in 2 minutes, ashley crosses the bridge in 5 minutes, jalen crosses the bridge in 10 minutes. how can the group cross the bridge in 17 minutes?

Step-by-step explanation:

Only two people can cross the bridge at the same time.

Chris takes 1 minute, Tracy takes 2 minutes, Ashley takes 5 minutes, Jalen takes 10 minutes.

Step 1: To make sure they all cross before 17 minutes is exceeded.

First, send Chris (the fastest) and Jalen (the slowest) together.

17 - 1 = 16

Chris crosses in 1 minute, Jalen, is still crossing (9 minutes left). 16 minutes left in all.

Next, Ashley crosses the bridge (5 minutes)

16 - 5 = 11

Ashley crosses with 11 minutes left, Jalen still has 4 minutes left, 11 minutes left in all.

Finally, Tracy crosses. Jalen would finish his crossing (4 minutes left). 11 minutes left in all.

11 - 4 = 7

The whole group costs with 7 minutes left in all

~

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this