the half-life of radium-226 is about 1,590 years. How much of a 100mg sample will be left in 500 years

Consider the reflection of parallelogram pqrs across the line of reflection, . if rr' = 14, then rz = . if sx = 5, then = 5.

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

2. explain in words how you plot the point (4, −2) in a rectangular coordinate system.