Who can help me?
1. I walked for 2 hour and ran for 3 hours. I can run twice as fast as i Walk. If i have travelled 32 km, find my walking speed.
2. A and B started walking at the same time from two placed 45 km apart. A's speed was 1 km/h more than B's speed. It they walked 5 hours to meet each other, find their speeds.
3.A car and Aa lorry start at the same time and in the same direction. Teh car's speed is twice that of the lorry. If the car travels 98 km more than the lorry after 3 hours, find their speeds.
4. The sum of two consecutive enen numbers is 26, What is the smaller number?
Math's questions?
2009-06-01 5:10 am
回答 (2)
2009-06-02 2:15 am
✔ 最佳答案
1)Let the walking speed be x km/h , then the running speed be 2x km/h
By distance=speed*time
32=2x+3(2x)
8x=32
x=4
So , the walking speed is 4 km/h
2)
Let the speed of A be x km/h , then that of B be (x-1) km/h
5x+5(x-1)=45
x+x-1=9
2x=10
x=5
A's speed is 5 km/h and B's speed is 4 km/h
3)
Let the lorry's speed be x km/h and the car's speed be 2x km/h
Since the car travels 98 km more than the lorry after 3 hours
2x(3)-x(3)=98
3x=98
x=98/3
The speed of the car is 196/3 km/h and that of the lorry is 98/3 km/h
4)
Let the smaller number be x , then the larger number be x+2
x+(x+2)=26
2x=24
x=12
The smaller number is 12
2009-06-01 1:19 pm
1. x = walking speed, 2x= running speed
2x+3*2x = 32 km
2x + 6x= 32km
8x = 32km
x =4km
my walking speed is 4 km
2. x+1= A speed, x = B speed
5(x+1) + 5x = 45
5x +5 +5x =45
10x+5 =45
10x=40
x=4
B speed is 4km/h, A speed is 5km/h
3. not sure of answer....
4. smaller no. = x, bigger number= x+2
x+x+2 = 26
2x+2=26
2x=24
x=12
smaller number is 12
2x+3*2x = 32 km
2x + 6x= 32km
8x = 32km
x =4km
my walking speed is 4 km
2. x+1= A speed, x = B speed
5(x+1) + 5x = 45
5x +5 +5x =45
10x+5 =45
10x=40
x=4
B speed is 4km/h, A speed is 5km/h
3. not sure of answer....
4. smaller no. = x, bigger number= x+2
x+x+2 = 26
2x+2=26
2x=24
x=12
smaller number is 12
收錄日期: 2021-04-22 00:38:50
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