Answer:
The number of fans remaining after the 3rd quarter=432 fans
Explanation:
Initial number of fans in the stadium=640
The number that went home by halftime=10% of Initial number=(10/100)×640=64 fans
Remaining fans=Initial number of fans-the number that went home
Replacing;
Remaining fans=(640-64)=576 fans
At 3rd quarter=25% of remaining fans left=(25/100)×576=144 fans
At 3rd quarter 144 fans also left
The remaining at 3rd quarter=(Remaining fans at halftime-Fans that left at 3rd quarter)
(576-144)=432 fans
The number of fans remaining after the 3rd quarter=432 fans