#1

#3**+1 **

1. If we set b to the number of total brothers, and s to the total number of sisters, we can write and solve the following system:

b - 1 = s (because the number of total brothers, minus Simon is equal to the number of sisters)

2(s - 1) = b (because twice the number of sisters, minus Sophia is equal to the number of brothers)

Solving for this gives us a total of 4 brothers and 3 sisters, meaning there are 7 total children (assuming all the brothers and sisters are children)

hope this helps (sorry if it took too long)

mitgliedd1
May 18, 2021

#4**+1 **

Let m be the total number of boys in the family, and f the total number of girls. Simon has m-1 brothers and f sisters, while Sophia has f-1 sisters and m brothers.

For Simon,

m-1 = f ==> m = f+1

For Sophia,

m = 2*(f-1) ==> m = 2*f - 2

Replacing m with f+1:

f + 1 = 2*f - 2 ==> f = 3

So m = 4, f = 3 from the first equation

Checking our work:

For Simon, 4–1 = 3; for Sophia, 4 = 2*(3–1)

TLDR: four boys and three girls in the family

KINGCASH
May 18, 2021