Solve the sum of two numbers is 23. one number is one less than twice the other. find the two numbers

An engineer scale model shows a building that is 3 inches tall. if the scale is 1 inch = 600 feet, how tall is the actual building?

Anew test for ra is being developed. the test is administered to 750 patients with ra and 750 without ra. for the sake of the question, assume the prevalence of ra in this population is 50%. of the 750 patients with ra, 575 have a positive result. of the 750 patients without ra, 150 have a positive result. what is the positive predictive value of the new test? a575/(575+150) b. 600/(600+ 150) c. 575/(575+125) d. 600/(600+ 125)

22 points algebra 1//sum and product of rational and irrational numbers. dont have to do all 4 if could much : )) write an example: 1) how the product of two identical irrational numbers can be a rational number. 2) how the product of two different irrational numbers can be a rational number. 3) write a quotient of intergers that is not a real number. 4) is the set of positive irrational numbers closed for the operation of division? if not give a counter example.