Ifu={12345678},a={1234},b={5678},th en find (a union b)`​

Need asap. solve for the following inequality

Edger needs 6 cookies and 2 brownies for every 4 plates how many cookies and brownies does he need for 10 plates

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)