Mom has 175 yuan in 10 yuan and 5 yuan RMB. The number of 10 yuan RMB is three times that of 5 yuan RMB. How many are 10 yuan RMB and 5 yuan RMB? Use arithmetic

Mom has 175 yuan in 10 yuan and 5 yuan RMB. The number of 10 yuan RMB is three times that of 5 yuan RMB. How many are 10 yuan RMB and 5 yuan RMB? Use arithmetic

If x sheets of 5 yuan are set, then:
5*X+10*3X=175
35X=175
X=5
So 15 for 10 yuan, 5 for 5 yuan

In a donation activity, class 6 (1) donated 240 yuan in total, including 50 pieces of RMB of 2 yuan, 5 yuan and 10 yuan, of which 2 yuan and 5 yuan are the same number, so how many pieces of RMB of 10 yuan?

Let 2 yuan and 5 yuan each be x pieces, then 10 yuan RMB is (50-2x) pieces, 2x + 5x + 10 (50-2x) = 240 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 13X = 260 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

Calculation: 20032003 × 2003-20032002 × 2002-20032002=______ ．

20032003 × 2003-20032002 × 2002-20032002 = 20032003 × 2003-20032002 × (2002 + 1) = 20032003 × 2003-20032002 × 2003 = 2003 × (20032003-20032002) = 2003 × 1 = 2003

A and B depart from a and B at the same time. A travels 120 km per hour, B 150 km per hour. (1) what is the speed ratio of a and B? (2) a

Speed ratio
=120：150
=4：5

1/2*(8-2x+8)*(6-x)=24

1/2*(8-2x+8)*(6-x)=24
(8-x)(6-x)=24
48-14x+x^2=24
x^2-14x+24=0
(x-2)(x-12)=0
x=2,x=12

1. The distance between the two places is 120 km. A and B two cars drive from the two places at the same time and travel two-thirds of an hour. The speed ratio of a and B two cars is 4:5. How many kilometers does a and B two cars travel per hour? 2. The table tennis number ratio of a, B and C is 9:4:2. A gives C 30 balls. B also gives C some balls. The table tennis number ratio of three people is 2:1:1. How many table tennis do B give C?

120 / 2 / 3 = 180 km / h a 180 * 4 / 9 = 80 km / H B 180 * 5 / 9 = 100 km / h

If the decimal point of a number is moved one place to the right, the number obtained is 2.25 larger than the original number, and the original number is______ ．

Let this number be X. because the decimal point of the decimal is moved one place to the right and expanded 10 times, the number obtained is 10x. According to the meaning of the title, we can get: & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 10x-x = 2.25 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 9x = 2.25 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X =

The speed ratio of the bus to the truck is 7:4. The two cars start from two places at the same time and run in opposite directions. They meet 18 kilometers away from the midpoint. How many kilometers did the bus travel?

The distance of the whole journey: 18 △ (74 + 7-12) = 132 (km), the kilometers of the bus: 132 × 711 = 84 (km)

The formula of triangle projection: a = bcosc + ccosb; b = ccosa + acosac; C = acosb + bcosa

On a section of double track railway, two trains are coming head on. The speed of train a is 20 m / s, and that of train B is 25 m / s. if the total length of train a is 200 m
In a section of double track railway, two trains pass at the same time. The speed of train a is 20 meters per second, and that of train B is 25 meters per second. If train a is 200 meters long and train B is 160 meters long, how long is the time for two trains to miss?

If opposite: (200 + 160) / (20 + 25) = 8s
If in the same direction, the express will overtake in the rear: (200 + 160) / (25-20) = 72s