Posted by mona on .
I need help with two problems to finish my assignment. #1 The length of a rectangle is fixed at 29cm. What widths will make the perimeter greater than 86 cm? If I could get the equation for this I would be able to figure it.
I saw this one posted and no response yet. #2 Trains A and B are traveling in the same direction. Train A is traveling at 100 mph and Train b is traveling at 110 mph. Train A passed a station at 1:15 pm and Train B passed the same station at 1:45pm. At what time will Train B catch up with Train A?

ALGEBRA 
Reiny,
first one:
let the width be w
remember P = 2(l+w)
so 2w + 58 > 86
etc.
for two:
let the time from the moment that train B passed the station to the moment it passes train A be t hours.
distance travelled by A since 1:45 pm is (50 + 100t)
(Distance = rate x time, so the 50 is the distance A went from 1:15 to 1:45, which was 1/2 hour)
distance traveled by B since 1:45 is 110t
so 110t = 50 + 100t
10t = 50
t = 5
so 5 hours from 1:45 pm or 6:45 pm 
ALGEBRA 
andrew,
how can i graph the inequality 4x+5y is greater than or equal to 20 in a plane?
#2 Please help to graph the system of inequalities y is less than or equal to 5 and x is less than or equal to 6 just finishing up an assignment thnaks 
ALGEBRA 
andrew,
Thanks Reiny