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on average, a person’s heart beats about 4.2×10^7times per year. there are about 7,600,000,000 people in the world. use this data to approximate the number of heartbeats for all the people in the world per year. expressing your answer in scientific notation in the form a×10^b, what are the values of a and b?

a=

b=

Design a number line containing five (5) points2.benin, one of the smallest countries in africa, has a total area of 43,475 square miles. the population of the country was recently estimated at 10,160,555. about 3,657,790 people live in rural areas. the country has only about 870 miles of surfaced roads. a. round off the total population to the nearest hundred thousand people. b. round off benin’s area in square miles to the nearest thousand. c. round off the number of miles of surfaced roads to the nearest ten. d. round off the number of people who live in rural areas to the nearest million.

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

Big boi and travis scott are performing at the super bowl. travis scott is 62 years younger than twice big boi’s age. the sum of their ages is 70 years old. use b to represent big boi’s age. write and solve an equation.