Craig plays goalie on his soccer team. Last week during practice, he blocked 21 out of 40 penalty kicks. This week, he attempted to block 50 penalty kicks. His success rate of stopping the kick in this week was 7.5% greater than last week. How many penalty kicks did Craig successfully stop this week?
Craig's success rate last week was 21/40 = <<21/40=0.525>>0.525.
This week, Craig's success rate was 0.075 + 0.525 = <<0.075+0.525=0.6>>0.6.
Craig successfully stopped 50 * 0.6 = <<50*0.6=30>>30 penalty kicks this week. Answer: \boxed{30}.