First, you should find a common denominator:
Turn 2/5 into 4/10 by multiplying by 2.
Then, find the difference in your fractions:
7/10 - 4/10 = 3/10.
Your answer is 3/10.
B because distributive property goes like this:
a(b+c)
a(b)+a(c)
That's just an example though
