Systems of equations word problem:

An airplane leave Chicago and heads towards Washington, which is 800 miles away.
Heading east, the plane, flying INTO the wind, takes 4 hours to get to Washington.
After refueling, the plane returns to Chicago, flying WITH the wind in three hours.
Find the speed of the wind.

Mary used 1/7 of a spool of ribbon to complete 4 projects. she used the same amount of ribbon on each project. how much ribbon did she use on each project?

Stefano accidentally dropped his sunglasses off the edge of a canyon as he was looking down. the height, h(t), in meters (as it relates to sea level), of the sunglasses after t seconds, is shown in the table. during its descent, the pair of sunglasses passed by a climber in the canyon 6 seconds after stefano dropped them. to the nearest meter, what is difference in elevation between stefano and the climber? 166 meters 176 meters 230 meters 240 meters its b.176 i took the test 166 is wrong and 176 is correct

Lines a and b are parallel. what is the value of x? -5 -10 -35 -55