On math question (will mark as brainliest)

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

Equal numbers of moles of he(g), ar(g), and ne(g) are placed in a glass vessel at room temperature. if the vessel has a pinhole-sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused?

Which best describes eras and periods?