Laura can make a set of cabinets by herself in 10 hours If L

Laura can make a set of cabinets by herself in 10 hours If Laura and Marcia work together, they can make the same set of cabinets in 6 hours. How long will it take Marcia working by herself to make the cabinets? A train and a car leave from Pasadena, California, railroad station at the same time headed for the state fair in Sacramento. The car averages 50 mph and the train averages 70 mph. If the train arrives at the fair 2 hours ahead of the car. find the distance from the railroad station to the state fair.

Solution

a) Laura takes ----10hrs to make 1 set of cabinets

So, 10hrs for --- 1 set

in 1hr ------- 1/10 of the cabinet

Then Laura +Marcia --- take 6 hrs

6hrs ----- 1 set

1 hr ----- 1/6 of a set

Marcia alone woud make in 1 hr ---(1/6 -1/10 ) = 4/60= 1/15th of 1 set of cabinet

So, Marcia would make 1 sewt of cabinet in 15 hrs

b) car speed = 50mph

train speed = 70 mph

distance between railroad station to fair be x

So, x/50 -x/70 = 2hrs

x( 1/50 -1/70) =2

x*20/50*70 = 2

x*1/(5*35) = 2

x = 10*35 = 350 miles