Question

Identify the corresponding word problem given the equation: x + 5 = 15
A) Billy is ten years older than his sister, Jenny. If Billy is 15 years old,
how old is Jenny?
Eliminate
B) Billy is five years older than his sister, Jenny. If Jenny is 15 years old,
how old is Jenny?
C) Billy is five years older than his sister, Jenny. If Billy is 15 years old,
how old is Jenny?
D) Billy is fifteen years older than his sister, Jenny. If Billy is 20 years old,
how old is Jenny?

Answer 1

Well, you can eliminate B.) right off the bat because it's not asking much: "If Jenny is 15 years old, how old is Jenny?"
And given that neither 10 nor 20 are included in the equation, you can eliminate both A.) and D.)

To check if C.) is correct, allow 'x' to represent Jenny's age, let 5 epresent the age difference between Jenny and Billy, and 15 as Billy's age.
If Billy is 15 years and 5 years older than Jenny (x), then Jenny must be 10 years old

x + 5 = 15
10 + 5 = 15

It checks out.