Question

plz solve for me i will mark brainlist​

Answer 1

Answer:

let Joseph weigh be x and his brothers weigh be y

x=3y

x+y=120

x=120-y

3(120-x)=x

360-3x=x

4x=360

x=90

y =30

Answer 2

Answer:

$3x + x = 120 \: 4x = 120 \: x = 120 \div 4 \: x = 30$