I need help on this question 7 - (-19) - 18 + (-19) + 18

Julie goes to the sports store and spends $40.50 before tax. she buys a pair of shorts for $21.75 and 3 pairs of socks that each cost the same amount. how much does each pair of socks cost? $$

Solve for n. round to the tenths place, if necessary. 14.2 cups of flour6 loaves of bread= 20 cups of flour n

Atourist boat is used for sightseeing in a nearby river. the boat travels 2.4 miles downstream and in the same amount of time, it travels 1.8 miles upstream. if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river.