Pema Dorji(boy) and Kezang Choden(girl) are two children in a family. Pema Dorji has thrice as many sisters as he has brothers. Kezang Choden has two less brothers than she has sisters. How many children are there in the family?

How many liters of peroxide should be added to 12 liters of an 8% peroxide solution so that the resulting solution contains 16% peroxide?   original added new amount of peroxide 0.96 liters x 0.96 + x amount of solution 12 liters x 12 + x 0.18 liter 1.14 liters 1.92 liters 2.10 liters