Amotorboat travels 9 miles downstream (with the current) in 30 minutes. the return trip upstream (against the current) takes 90 minutes.

which system of equations can be used to find x, the speed of the boat in miles per hour, and y, the speed of the current in miles per hour? recall the formula d = rt.

9 = 0.5(x _ y)
9 = 1.5(x + y)

9 = 1.5(x _ y)
9 = 0.5(x + y)

0.5 = 9(x _ y)
1.5 = 9(x + y)

1.5 = 9(x _ y)
0.5 = 9(x + y)

The chemical effect of the endocrine system is longer lasting than the chemical effect of the nervous system. select the best answer from the choices provided t f

Match each vocabulary term to its definition. 1. electrons neutral subatomic particles found in the nucleus of the atom 2. neutron lowest energy position of an electron in an atom 3. photon the path of an electron around the nucleus of an atom 4. ground state negatively charged, subatomic particles 5. protons packet of energy of specific size 6. element substance with only one type of atom 7. orbital positively charged, subatomic particles found in the nucleus of the atom

Why does lightning travel from clouds to the ground?