A group of boy scouts and girls scouts is going on a rafting trip. 80% of the scouts arrived with signed permission slips. If 40% of the scouts were boy scouts and 75% of the boy scouts arrived with signed permission slips, then what percentage of the girl scouts arrived with signed permission slips? Round to the nearest percent.  Select:
A) 79
B) 81
C) 82
D) 83
E) 85

Rationale: "40 % were boy scouts so 60 % ( 100 - 40 = 60 ) were girl scouts . # of boy scouts with permission slips signed + # of girl scouts with permission slips signed = total # with permission slip signed ( 75 % of 40 % of the total going ) + ( ? % of 60 % of the total going ) = 80 % of the total going we can let the ` ` total going ' ' = 100 arbitrarily since we only care about the percent ( of girl scouts w / permission signed ) . 75 * . 40 * 100 + x * . 60 * 100 = . 80 * 100 30 + x * 60 = 80 60 x = 50 x = 50 / 60 x = . 833333 converting this to a percent , we have 83 % d"
Answer: D