Question

One number is two times another. The sum of the number is 90 what are the two numbers

Answer 1

one number is 2 times another
x=2y

sum is 90
x+y=90

easy
x=2y
sub 2y for x
2y+y=90
3y=90
divide both sides by 3
y=30

sub back
x=2y
x=2(30)
x=60

the numbers are 60 and 30