51/8 times 17/4and simplified

Ivan and jeff buy a package of 8 pens for $4.00. ivan wants 5 of the pens, and jeff wants 3.how much should each student pay?

Asap describe the transformations required to obtain the graph of the function f(x) from the graph of the function g(x). f(x)=-5.8sin x. g(x)=sin x. a: vertical stretch by a factor of 5.8, reflection across y-axis. b: vertical stretch by a factor of 5.8,reflection across x-axis. c: horizontal stretch by a factor of 5.8, reflection across x-axis. d: horizontal stretch by a factor of 5.8 reflection across y-axis.

Ineed i been stuck on this question since yesterday