I know this is a simple question but i am confused hah, can someone help me

You are remodeling your kitchen. you’ve contacted two tiling companies who gladly told you how long it took their workers to tile of a similar size jim completed half the floor in 8 hours. pete completed half of the other floor in 7 hours. if pete can lay 20 more tiles per hour than jim, at what rate can jim lay tiles

Evaluate cos2θ for cosθ = square root of 3/2

Can someone me out here number 4 plz