At a used book sale, 4 books cost $20. What is the cost per book? * HELP PL

Afruit stand has to decide what to charge for their produce. they need $10 for 4 apples and 4 oranges. they also need $15 for 6 apples and 6 oranges. we put this information into a system of linear equations. can we find a unique price for an apple and an orange?

Mr. thompson is on a diet. he currently weighs 260 pounds. he loses 4 pounds per month. what part of the story makes the relationship not proportional?

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236