Rob Is saving to buy a new MP3 player. For every $15 he earns babysitting, he saves $5. On Saturday, Rob earned $60 babysitting. How much money did he save?
he eamed $60, he saved $

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