Nancy spent half of her allowance going to the movies. She washed the family
car and earned 7 dollars. What is her weekly allowance if she ended with
16 dollars ?

Nancy's weekly allowance is
12
dollars.
Explanation:
Ler weekly allowance be
x
dollars.
She spent half of it i.e.
x
2
going to movies. Her balance was
x
−
x
2
.
She then earned
7
by washing family car, which made her balance
x
−
x
2
+
7
.
As she ended with
13
dollars, we have
x
−
x
2
+
7
=
13
or
x
2
=
13
−
7
=
6

Hence
x
=
6
×
2
=
12
and
Nancy's weekly allowance is
12
dollars.

Figure it out your self