6. A laptop computer sells for $2,149.99 and has a $200 mail-in rebate. What is the cost after the rebate if an envelope costs
$0.20 and a Forever stamp costs $0.41?

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

The contents of 3838 cans of coke have a mean of x¯¯¯=12.15x¯=12.15. assume the contents of cans of coke have a normal distribution with standard deviation of σ=0.12.σ=0.12. find the value of the test statistic zz for the claim that the population mean is μ=12.μ=12.

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under