The answer is 1.
7 x 1 = 7
and 10 x 1 = 10
They don't have other factors in common besides 1.
In this problem, we have to find the factor which will
make (1 / 10) equal to (2 / 5). Therefore we can write it as:
x (1 / 10) = 2 / 5
where x is the number of people who ate the blueberries
x = (2 / 5) / (1 / 10)
x = 4
<span>Therefore 4 people ate the blueberries.</span>