3people bill come to $30 but is $25 where does the other $1 go

Sam claims that cos x =sin y if x and y are congruent angels. is sam correct ?

Which number produces a rationale number when multiplied by 1/5

Find the volume of the described solid.the solid lies between planes perpendicular to the x-axis at x = 0 and x=7. the cross sectionsperpendicular to the x-axis between these planes are squares whose bases run from the parabolay=-31x to the parabola y = 30/x.a) 441b) 147c) 864d) 882