Kinda forgot how to do this but i got 894.09 for my answer not sure if im right

Cody worked 42.5 hours per week in july. this is 12.25 hours more per week than he worked in june.how many hours did cody work per week in june?

In the film, zeke the zombie slayer versus the zombies from space, zeke slayed 140 zombies. in the sequel, zeke the zombie slayer versus the zombies from space, part 2, he slayed 5% more zombies. how many zombies were slain by zeke in the sequel?

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed