If $20\%$ of a school was made up of out-of-district students last year, but the number of out-of-district students increased by $50\%$ this year, without any change in total enrollment, what percent of the students is out-of-district this year?
Let x be number of total enrolled then 20% of the OD, out of district, students would be 0.2x. The number is increased by 50%, 1.5 so (0.2x)(1.5)=0.3x, so 30% of the total enrolled is out of district.
