Please help fast I want to know how to create a website using bootstrap jQuery Ajax json ad crud operations via mongodb​

What is the largest decimal number that can be represented by a binary number with 4 place values? (remember, each place in a binary number has a value of a power of 2, starting in the ones place with 20.)

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)?

How should you specify box sizes on a web page if you want the boxes to vary according to the font size of the text they contain? a. in pixels b. in inches c. as percentages d. in em units