Answer:
50 days
Explanation:
It's simple, we just have to express this as an equation.
x we will take it as the number of days we do not know.
so..
(0.2 M * x) = 10 M
we divide on both sides by 0.2 M.
x * 0.2 M / 0.2M = 10 M / 0.2 M
we simplify
x = 10M / 0.2 M
finally we only solve and the result of x will be the days it took.
x = 50
50 days