Answer:
60 boys
Step-by-step explanation:
boys : girls = 3 : 5
Total number of people = 160
Let y = common factor:
Therefore, 3y + 5y = 160
⇒ 8y = 160
⇒ y = 160 ÷ 8 = 20
Boys = 3y = 3 x 20 = 60
Girls = 5y = 5 x 20 = 100
So there are 60 boys and 100 girls

The sign at the end changes because both sides of the equation are being divided by a negative number.
Answer:
5
Step-by-step explanation:
(13^2 - 12^2) ÷ 5
(169 - 144) ÷ 5
25 ÷ 5
5