Two trains are moving towards each other. One train moves at a speed of 50 mph, and the other train travels at 70 mph. How soon will they meet, if originally the distance between them was 390 miles?

Plzzz plzz maths ! quadratic sequences =an^2+bn 1) 1,6,15,28,45 2)5,18,39,68,105 3) 1,8,21,40,65 4) 7,24,51,88,135 5) -1,2,9,20,35

The volume of gas a balloon can hold varies directly as the cube of its radius. imagine a balloon with a radius of 3 inches can hold 81 cubic inches of gas. how many cubic inches of gas must be released to reduce the radius down to 2 inches?

Jahdzia wears her winter coat when the temperature is colder than -4 degrees celsius. write an inequality that is true only for temperatures (t) at which jahdzia wears her winter coat.