Somebody help ya girl out!

The dance committee of pine bluff middle school earns $72 from a bake sale and will earn $4 for each ticket they sell to the spring fling dance. the dance will cost $400 write an inequality to determine the number, t of tickets the committee could sell to have money left over after they pay for this year's dance. what is the solution set of the inequality?

Two trains leave stations 546 miles apart at the same time and travel toward each other. one train travels at 95 miles per hour while the other travels at 115 miles per hour l. how long will it take for the two trains to meet

You use technology ans find a sum of 6.712e-8. write this sum in standard form