I need help with the please

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

An english teacher would like to divide 8 boys and 10 girls into groups, each with the same combination of boys and girls and nobody left out. what is the greatest number of groups that can be formed?

Following are uses of spreadsheets. for each use, choose whether the use is a business use, consumer use, or student use. family budget: sales data: recording research data for science class: