Ratio is 3:4, so that means the total number of 182 can be divided into 7 parts. 182 divided by 7 is 26, so each part is 26. The ratio of girls is 3, so 3 times 26 is 78. You can check this by putting (3*26)/(4*26) simplifies to 78/104 to 3/4 which is the right ratio