(1) The distance between a and B is 264 km. A takes a bus from a to B, with an average of 80 km per hour. B takes a motorcycle from B to a, with an average of 32 km per hour. When a meets B after 200 km, how many hours ahead of B? (2) A supermarket bought 100 pens at the price of 5 yuan per pen. When they were sold, they were priced at 8 yuan per pen. When some of them were sold, the remaining pens were sold at a 10% discount. When all the pens were sold, a total profit of 288 yuan was made. How many pens were sold at a 10% discount? I knelt down and begged

(1) The distance between a and B is 264 km. A takes a bus from a to B, with an average of 80 km per hour. B takes a motorcycle from B to a, with an average of 32 km per hour. When a meets B after 200 km, how many hours ahead of B? (2) A supermarket bought 100 pens at the price of 5 yuan per pen. When they were sold, they were priced at 8 yuan per pen. When some of them were sold, the remaining pens were sold at a 10% discount. When all the pens were sold, a total profit of 288 yuan was made. How many pens were sold at a 10% discount? I knelt down and begged

1.264-200 = 64 (km) 64 △ 32 = 2 (H) 200 △ 80-2 = 0.5 (H)
2.5 × 100 + 288 = 788 yuan the pen with a price of 8 yuan sold x pieces
8x+8×0.9×(100-x)=788
x=85
100-85 = 10% off 15 pens sold

A math problem, I want to sleep
A peddler carried two bags of mung beans and yelled: 3000 grams of rice for one kilogram of mung beans. Aunt Li heard the cry and brought a pot of rice for mung beans. The peddler put the rice on the scale, just 3000 grams. Then she weighed one kilogram of the rice for Aunt Li and asked who would lose in such a deal?

Assuming the dish weight is XKG, the mung bean weighs (1-x) kg, which should be replaced by (3-3x) kg rice. But in fact, with (3-x) kg rice, Aunt Li loses 2xkg rice

If the three sides of an obtuse triangle are a, A-1 and A-2, and the maximum angle is not more than 120 degrees, then the value range of a is?

First, if the three sides are greater than 0, find the solution
2 a-1+a-2>a
3 cosa (maximum angle) = ((A-1) ^ 2 + (A-2) ^ 2-A ^ 2) / 2 (A-1) (A-2) the formula is greater than or equal to - 1 / 2 and less than 0. Please find the solution
Let's find the intersection of the two