Robert bought one 4.5-lb bag of dog food for $3.89, a 7.5-lb bag of cat food for $6.69, and two 2.3-lb bags of birdseed for $1.89 each. how much did he pay for the animal food?

On an airplane there are two seats on the left side and three seats on the right side there are 90 seats o the right side of the plane

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?