How many different ways can 4 students be chosen from a group of 20

Johnny rode his bike to a friends house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was unable to play. what was his displacement for the total bike ride trip? what could you use as a reference point ? show the steps to solve this problem.

597008.439431 to the nearest thousand

4. bob solved the inequality problem below incorrectly. explain his error and redo the problem showing the correct answer. ? 2x + 5 < 17 ? 2x + 5-5 < 17-5 -2x/-2 < 12/-2 x < -6