Question

A car travel 30 km at uniform.
40 k/h and next 30 km
20k/h Find average speed​

Answer 1

Answer:

Explanation:

Given :-

1st Case

Distance, s = 30 km

Speed, v = 40 km/hr

2nd Case

Distance, s = 30 km

Speed, v = 20 km/h

To Find :-

Average Speed

Formula to be used :-

Speed = Distance / Time

Time = Distance / Speed

Average Speed =Total distance/ Total time

Solution :-

1st Case

Time = Distance / Speed

Time, t = 30 / 40

t = 3/4 hrs

2nd Case

Time = Distance / Speed

Time, t = 30 / 20

t = 3/2 hrs

Average Speed =Total distance/ Total time

= (30 + 30) / (3/4) + (3/2)

= 60 / ( 3 + 6 ) /4

= 60 / 9 × 4

= 20 / 3 × 4

= 80 / 3

= 26.67 Km/h ( Approx. )

Hence, The average speed​ of car is 26.67 Km/h.

Answer 2

ɢɪᴠᴇɴ ᴛʜᴀᴛ ,

   

⑴sᴛ 30 ᴋᴍ ᴜɴɪғᴏʀᴍ sᴘᴇᴇᴅ ɪs (ᴜ1) = 40 ᴋᴍ/ʜ 

     

⑵ɴᴅ 30 ᴋᴍ ᴜɴɪғᴏʀᴍ sᴘᴇᴇᴅ ɪs ( ᴜ2 ) = 20 ᴋᴍ/ʜ

SoLuTiOn ,

     

ᴛᴏᴛᴀʟ ᴅɪsᴛᴀɴᴄᴇ ( ᴅ ) = 30 + 30 = 60ᴋᴍ

     

ᴛɪᴍᴇ ᴛᴀᴋᴇɴ ɪɴ ⑴sᴛ ᴛɪᴍᴇ = ᴅ / ᴛ = 30/40

ᴀʟsᴏ, ⑶ʜ / ⑷ = 180/⑷ = 45 ᴍɪɴ

   

ᴛɪᴍE ᴛᴀᴋᴇɴ ɪɴ ⑵ɴᴅ ᴛɪᴍᴇ = ᴅ/ᴛ = 30/20

ᴀʟsᴏ, 3ʜ/⑵ = 180/⑵ = 90 ᴍɪɴ

   

ᴛᴏᴛᴀʟ ᴛɪᴍᴇ = 45 + 90 = 135 ᴍɪɴ = 135/60 ʜ

ᴀᴠG. sᴘᴇᴇᴅ = 60/135/60 = 60* 60/135 =

26.66 ᴋᴍ/ʜ ( ᴀɴsᴡᴇʀ )