Give an example of a stratified random sample

Liesl grew 7/12 of a foot in one year. her little sister grew 1/3 of a foot during that same year. how much more did liesl grow than her little sister did

Kelly is a salesperson at a shoe store, where she must sell a pre-set number of pairs of shoes each month. at the end of each work day the number of pairs of shoes that she has left to sell that month is given by the equation s=300-15x , where s is the number of pair of shoes kelly still needs to sell and x is the number of days she has worked that month. what is the meaning of the number 300 in this equation

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.