Answer:
10 offices
Step-by-step explanation:
the ratio is 5/6 so if the time is doubles the number of offices cleaned also doubles.
5/6 x 2 =10/12 so, 10 offices cleaned.
It is an arithmetic because it is adding 2 to each number.
I don't think he will have enough flour I guess, but from my perspective when I divided and multiplied and whatnot I didn't get a whole number. I got mostly decimals, so I think there won't be enough flour.
Nearest 10 is according to the last digit.
if the digit is >5, it +1 to the tenth digit. If it's <5, it will be reduced to 0.
for your case, 392, 2 < 5, therefore rounded up to nearest tenth is 390.