Age (years) Population Under 15 138
15 - 64 6978
Over 64 324

Calculate the old age dependency ratio from the chart above. Round to 4 decimals places.

Create and solve a linear equation that represents the model, where squares and triangles are shown evenly balanced on a balance beam. assume the weight of a square is 1 unit and the weight of a triangle is unknown.

What are the solutions of the system? solve by graphing. y = -x^2 -6x - 7 y = 2

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of