Carol’s book shelf has 4 shelves with 6 books on each. her brother robert has 3 shelves with 7 books on each. they want to combine their books. if they put 9 books on a shelf, how many shelves will they need?

Enter the missing numbers in the boxes to complete the table of equivalent ratios.time (min) distance (km)? 36 9? 1512 ?

Lucy is a dress maker. she sews \dfrac47 7 4 of a dress in \dfrac34 4 3 hour. lucy sews at a constant rate. at this rate, how many dresses does lucy sew in one hour? include fractions of dresses if applicable

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?