In 36.5 weeks, Miguel raised $2372.50 for cancer research. How much money will he raise 20 weeks ?

This is a situation of direct variation.

Less number of weeks —-> amount raised will be less .
Given :
Miguel raised $2,372.50 in 36.5 weeks
Amount raised in one week is
= 2372.5 / 36.5
= $65
Amount raised in 20 weeks is
= 65 x 20
= $1300
Hence, the money raised in 20 weeks is $1300