Help please ! The sphere’s radius (r) is...
A. (3V/4pi)1/3
B. (4V/3pi)1/3
C. (3pi/4V)1/3

Ineed to learn how to solve this problem

Select the sequences that are geometric.

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling