Who know the answer to 7/12+5/12 i think its 12/12 but im not sure

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.

3/4 = c/36 i need with this fraction proble.