Interval 7-0 I don’t know how to do this at all could you show work and explai, much appreciated

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years

In the sixth grade 13 out of 20 students have a dog if there are 152 sixth grade students how many of them have a dog