Which statement explains one reason why unconfirmities occur

Unconformities occur when either erosion wears away rocks, or rock deposits never form. Therefore, a time gap exists between when the rocks below the unconformity formed and when those above it formed. ... Common to all three, erosion causes them to form, and younger rocks sit on older rocks.

We will use the property :

sum of interior angles on same side of transversal =180

(8x-14) + (2x+54)=180

10x+40=180

10x=140

x=14