Question

Jean surveyed 25% of all eighth graders and 75% of all 7th graders. John surveyed 50% of all eighth graders and 50% of all 7th graders at the same school.

Jean surveyed a total of 152
John surveyed a total of 144

What is the number of eighth graders?
Steve
if there are x 7th-graders and y 8th-graders,

.75x+.25y=152
.50x+.50y=144

(x,y) = (160,128)