The word population in 2013 was about 7.125 billion. in 2003, it was about 6.357billion. which number represents the increase in the world population between 2003 and 2013? a; 0.0768x10/7 b; 0.768x 10/8 c; 7.68x 10/9 d; 7.68x 10/8

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.