There is a kind of disinfectant with a net weight of 250g. Now we need to disinfect the desks and chairs in the classroom according to the above reference manual. How many kg of water does this bottle of disinfectant need? Disinfection reference manual Scrub for 5 to 10 minutes 1. Fruits, tableware, kitchen supplies 1:500 2. White clothes and instant noodles 1:300 3. The contaminant ratio of infectious patients is 1:100

There is a kind of disinfectant with a net weight of 250g. Now we need to disinfect the desks and chairs in the classroom according to the above reference manual. How many kg of water does this bottle of disinfectant need? Disinfection reference manual Scrub for 5 to 10 minutes 1. Fruits, tableware, kitchen supplies 1:500 2. White clothes and instant noodles 1:300 3. The contaminant ratio of infectious patients is 1:100

According to the meaning of the title, water should be added at the ratio of 1:300
1 g water 300 g
250g water: 300 × 250 = 75000g = 75kg
This bottle of disinfectant needs 75 kg of water

First, find out the law according to the following calculation, and then evaluate
1.2^2=1.44 12^2=144 120^2=14400 0.12^2=0.0144 0.012^2=0.000144
① If 2.42 ^ 2 = 5.8564, calculate the value of 24.2 ^ 2
② If 1.23 ^ 2 = 1.5129, y ^ 2 = 0.00015129 and Y > 0, find the value of Y

1.2^2=1.44 12^2=144 120^2=14400 0.12^2=0.0144 0.012^2=0.000144
① If 2.42 ^ 2 = 5.8564, then
24.2^2=585.64
② If 1.23 ^ 2 = 1.5129, y ^ 2 = 0.00015129 and Y > 0, find the value of Y
y=0.0123

Xiaoming went to buy notebooks, and bought five first. Later, he found that there were more than six notebooks, and the mall gave him a 60% discount. Xiaoming bought eight more. It turned out that he saved 1 yuan more than five, and Xiaoming spent a total of 10 yuan______ Yuan

1 △ 5-8 × 60% × 5 × 2-1, = 1 △ 5-4.8 × 5 × 2-1, = 1 △ 0.2 × 5 × 2-1, = 50-1, = 49 yuan