A box of blueberries is 2/5 full. Janet and her friends had each eaten 1/10 of a box of blueberries. How many people are blueberries?

The question is about the number of people who ate blueberries. The sum of their consumption must equal to 2/5. Since each consumption is 1/10, the equation is written as

2/5 = (1/10) x

where x is the number of people who ate the blueberries

Cross-multiplying,

20 = 5x

x = 20/5 = 4

Thus, there were 4 people who ate the blueberries.

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

Therefore 4 people ate the blueberries.