Unit rate
A rate is a unit rate when the denominator is 1. Then, in each part we must simplify the fractions so we find them as a unit rate:

3 Tbsp/2 tsp = 1.5 Tbsp / tsp

135 piches/45 strikes = 3 pitches / strike

128 miles/4 hours = 32 miles/hour

2250 pencils/18 boxes = 125 pencils/box