Answer:

A. 2/3

Step-by-step explanation:

1/5×_+1/3=7/15

1/5×_=7/15-1/3

1/5×_=7/15-5/15

1/5×_=2/15

2/15÷1/5=_

2/15×5=_

=10/15

=2/3

let's check

1/5×2/3+1/3=7/15

PEMDAS(Parenthesis, Exponents, Multiplication, Division, Addition, and Subtraction)

1/5×2/3=2/15

2/15+1/3=2/15+5/15

=7/15

1/5×2/3+1/3=7/15