<PRE><B>Question 291181</B>
Again RATE (SPEED) X TIME = DISTANCE
IN THIS PROBLEM WE ARE ADDING TWO DIFFERENT TIMES TO TOTAL THREE HOURS.
STOPP!! UNDERSTAND THIS CONCEPT HERE--ONE TIME PLUS ANOTHER TIME ADDS UP TO THREE HOURS.

NOW IN THE FORMULA ABOVE WE REPRESENT TIME BY DISTANCE OVER SPEED.
SO, THE D/S (TIME IT TAKES TO TRAVEL FROM  ALB. TO ROS.) + D/S (TIME IT TAKES TO TRAVEL FROM ROS. TO CARL.) =3 HOURS. 

NOW TOTAL DISTANCE IS 220 MILES. SO LET 220-X/75 BE THE TIME IT TAKES TO DRIVE TO ROS.
LET X/70 BE THE TIME IT TAKES TO DRIVE TO CARL.

THEN WE HAVE 3 HOURS = 220-X/75 + X/70
MULTIPLY THRU BY (75)(70) TO REMOVE THE DENOMINATOR--REVIEW ADDING FRACTIONS IF NEED BE HERE.
WE GET 15,750=15,400 -70X + 75X
                    350=5X
                       70=X
WE SUBSTITUTE BACK INTO 220-X/75, WE GET 150/75=2HOURS    A) IS THE ANSWER</PRE>