On Saturday, my mother and I went to our hometown in the country. Along the way, I saw farmers' uncles harvesting sweet potatoes. They smile at the farmer's uncle like fat dolls. My mother told me, "It's sweet potato harvest season", and then she said to herself, "Today, sweet potatoes are rich again." I said, "What's the use of collecting so many sweet potatoes?" Mom said: "Sweet potato can play a great role! Can be made into sweet potato skin, sweet potato powder, sweet potato strips ... "

Knowing that I had learned the percentage, my mother asked me: 50 Jin of sweet potato can squeeze out 5 Jin of sweet potato powder. What is the flour yield of these sweet potatoes? If grandma squeezes 500 Jin of sweet potatoes this year, how much sweet potato powder can grandma collect? I calculated:

5/50× 100%=0. 1× 100%= 10%

500× 10%=50 (kg)

After I finished the calculation, I said to my mother, "The output of sweet potato powder is 10%, and grandma can receive 50 Jin of sweet potato powder this year." I asked my mother curiously, "What does Grandma do with so much sweet potato powder?" Grandma said, "Our special snack in Pingtan-salty rice is indispensable. Our family of three needs 0.4 Jin of sweet potato flour for a salty rice meal. Then grandma gave us 10 Jin, so how many times can we cook salty rice? " I calculated:

10 ÷ 0.4 = 25 (times)

I said to my mother, "I can do it 25 times." Mom said: "Eat salty rice twice a month on average, is it enough for one year?" I said, "I can't finish it yet. I can add another meal during the Chinese New Year. " Mom said, "You are really good. In fact, it can also be made into vermicelli soup, vermicelli and vermicelli knot. "