Checking calculation of mathematical jokes

Xiaoyun has a private car and uses 93 # gasoline. When the oil price is 5.20 yuan/liter, the average monthly postage is 780 yuan. Now that the oil price has risen by 0.30 yuan per liter, how much will it cost every month? (Assuming all other factors remain constant)

(5.2+0.3)× 780/5.2=825

Please take a point on one side of the triangle and connect it with the vertex opposite to that side with a ruler, so as to divide the triangle into two parts, A and B, so that the ratio of the areas of the two parts is 3:2 (please calculate continuously before drawing).

2+3 = 5 A and B account for 3/5 and 2/5 of the bottom respectively.

Party A and Party B run 100 meters and start at the same time. Party A runs 80 meters and Party B runs 60 meters. At this speed, Party A ran to the finish line. How many meters to the finish line?

80/60 = 100/( 100-x)x =(800-600)/8 = 25

A cylindrical oil drum is filled with three quarters of oil, and 20% of the gasoline in the drum is poured out, leaving 200 liters. How many liters of gasoline were there in the oil drum?

200/( 1-0.2)=250

The original price of a commodity is 24 yuan, and the price is reduced on May 1st. On that day, sales increased by half and revenue increased by 25%. How much is the price reduction of this commodity?

The purchase price is one yuan, and the price is reduced to X yuan,1.5 (x-a) =1.25 (24-a) x = (120-a)/6.

In a cylindrical measuring cup with a bottom diameter of 8 cm and a height of 10 cm, the water surface is 8 cm high. Immerse a ball in water and it will overflow 50 grams when it is full. What is the volume of this ball? (1 cubic centimeter of water weight 1 gram)

π*4*4*2+50=32π+50= 150.48