question for algebra

Question

A number is 2/3 of another number. If the sum of the two numbers is 30, find the smaller number.

Answer 1

I would approach it like this.

X + Y = 30

X = 2/3 Y

Then substitute the 2/3 Y for the X in the first equation.

2/3 Y + Y = 30

The rest would be the same as Mark’s

Ending with

Y = 18

X = 2/3 Y

X = 2/3 (18)

X = 12

Which is what the directions tell you to look for

Answer 2

n + (2/3)n = 30

(5/3)n = 30

5n = 90

n 18