In a school gym, the ratio of the number of boys to girls was 4:3. After 160 boys left the gym, the ratio become 4:5. How many girls were there in the gym

Girls never change number

make same

4:3 times 5 is 20:15

4:5 times 3=12:15

boys:girls

from 20:15 to 12:15

boys dropped 160

20-12=8

160=8 units

divide both sides by 8

20=1unit

girls=15 units

20*15=300

300 girls