21.  Mac travels from A to B a distance of 250 miles in 5 1/2 hours. He returns to A in 4 hours 30 minutes. his average speed is?

44 mph
46 mph
48 mph
50 mph

```Answer

Answer: Option  D Explanation:Speed from A to B =(250*2/11) mph = (500/11) mph.
Speed from B to A =(250*2/9) mph = (500/9) mph.
Therefore average speed =(2*500/11*500/9/500/11+500/9) mph = (500000/4500+5500)mph = 50 mph ```

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22.  A car drive travels from the plains to the hill station, which are 200 km apart at an average speed of 40 km/hr. In the return the trip, he covers the same distance at an average speed of 20 km/hr. the average speed of the car over the entire distance of 400 km is?

25 km/hr
26.67 km/hr
28.56 km/hr
30 km/hr

```Answer

Answer: Option  B Explanation:Average speed = (2*40*20/ 40+60) km/hr = 80/3 km/hr = 26.67 km/hr. ```

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23.  A person travels from P to Q at a speed of 40 kilometer per hour and returns by increasing his speed by 50%. What is his average speed for both the trips?

36 kilometer per hour
45 kilometer per hour
48 kilometer per hour
50 kilometer per hour

```Answer

Answer: Option  C Explanation:Speed on return trip = 150% of 40 = 60 kilometer per hour.
therefore average speed = (2*40*60/40+60) km/hr = (4800/100)km/hr = 48 km/hr. ```

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24.  A is faster than B. A and B each walk 24 km.The sum of their speeds is 7 km/hr and the sum of times taken by them is 14 hours.Then A's speed is equal to:

3 km/hr
4 km/hr
5 km/hr
7 km/hr

```Answer

Answer: Option  B Explanation:Let A's speed = x km/hr. Then B's speed =(7-x) km/hr
24/x + 24/(7-x) = 14
24 (7-x) +24x = 14x (7-x)
= 14 x^2 - 98x + 168 =0
x^2 -7x +12= 0
(x-3) (x-4) = 0
x=3 or x= 4
Since A is faster than B, so A's speed = 4km/hr and B's speed = 3km/hr. ```

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25.  A farmer traveled a distance of 61km in9 hrs. He traveled partly on foot @ 4 km/hr and partly on bicycle @ 9 km/hr.The distance traveled on foot is:

14 km
15 km
16 km
17 km

```Answer

Answer: Option  C Explanation:Let the distance traveled on foot be x km
then distance traveled on bicycle =(61-x)km
so x/4 + (61-x)/9-9 =9x+ 4(61-x)
= 9*36 = 5x =80 = x=16km ```

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