Question

One number is 4 more than another, and their sum is 60. What is the smaller number?

If x = the larger number and y = the smaller number, then which of the following systems could be used to solve the problem?
a)x + y = 60 and -x + y = 4
b)x + y = 60 and x - y = 4
c)x + y = 60 and x + y = 4

Answer 1

y=smaller number, given
x=y+4, given
y+y+4=60 (substituting y+4 for x), given
2y+4=60, 2y=56, y=28 then x=28+4=32
looking at the answers which are true? b